diff --git a/stdlib/public/Platform/CMakeLists.txt b/stdlib/public/Platform/CMakeLists.txt
index 6b878c8cded8c..31419b092c057 100644
--- a/stdlib/public/Platform/CMakeLists.txt
+++ b/stdlib/public/Platform/CMakeLists.txt
@@ -161,8 +161,9 @@ add_swift_target_library(swiftMusl ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OV
       ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
       ${swift_platform_compile_flags}
     LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-    TARGET_SDKS MUSL
-    INSTALL_IN_COMPONENT sdk-overlay)
+    TARGET_SDKS LINUX_STATIC
+    INSTALL_IN_COMPONENT sdk-overlay
+    DEPENDS musl_modulemap)
 
 add_swift_target_library(swiftWASILibc ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OVERLAY
     ${swift_platform_sources}
@@ -198,6 +199,80 @@ add_swift_target_library(swiftCRT ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_SDK_OVE
     TARGET_SDKS WINDOWS
     INSTALL_IN_COMPONENT sdk-overlay)
 
+foreach(sdk ${SWIFT_SDKS})
+  # Add more platforms supporting Musl to these checks,
+  if(NOT "${sdk}" STREQUAL "LINUX_STATIC")
+    continue()
+  endif()
+
+  set(musl_modulemap "musl.modulemap")
+  set(musl_header "SwiftMusl.h")
+
+  foreach(arch ${SWIFT_SDK_${sdk}_ARCHITECTURES})
+    set(arch_subdir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${arch}")
+    set(module_dir "${SWIFTLIB_DIR}/${arch_subdir}")
+    set(module_dir_static "${SWIFTSTATICLIB_DIR}/${arch_subdir}")
+
+    set(musl_modulemap_out "${module_dir}/${musl_modulemap}")
+    set(musl_modulemap_out_static "${module_dir_static}/${musl_modulemap}")
+    set(musl_header_out "${module_dir}/${musl_header}")
+    set(musl_header_out_static "${module_dir_static}/${musl_header}")
+
+    add_custom_command_target(
+      copy_musl_modulemap
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "make_directory" ${module_dir}
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "copy"
+          ${CMAKE_CURRENT_LIST_DIR}/${musl_modulemap}
+          ${musl_modulemap_out}
+      COMMAND
+        "${CMAKE_COMMAND}" "-E" "copy"
+          ${CMAKE_CURRENT_LIST_DIR}/${musl_header}
+          ${musl_header_out}
+      OUTPUT ${musl_modulemap_out} ${musl_header_out}
+      COMMENT "Copying Musl modulemap to resources")
+
+    list(APPEND musl_modulemap_target_list ${copy_musl_modulemap})
+
+    if(SWIFT_BUILD_STATIC_STDLIB OR SWIFT_SDK_${sdk}_STATIC_ONLY)
+      add_custom_command_target(
+        copy_musl_modulemap_static
+        COMMAND
+          "${CMAKE_COMMAND}" "-E" "make_directory" ${module_dir_static}
+        COMMAND
+          "${CMAKE_COMMAND}" "-E" "copy"
+            ${CMAKE_CURRENT_LIST_DIR}/${musl_modulemap}
+            ${musl_modulemap_out_static}
+        COMMAND
+          "${CMAKE_COMMAND}" "-E" "copy"
+            ${CMAKE_CURRENT_LIST_DIR}/${musl_header}
+            ${musl_header_out_static}
+        OUTPUT ${musl_modulemap_out_static} ${musl_header_out_static}
+        COMMENT "Copying Musl modulemap to static resources")
+
+      list(APPEND musl_modulemap_target_list ${copy_musl_modulemap_static})
+
+      swift_install_in_component(FILES "${musl_modulemap_out_static}"
+                                 DESTINATION "lib/swift_static/${arch_subdir}"
+                                 COMPONENT sdk-overlay)
+      swift_install_in_component(FILES "${musl_header_out_static}"
+                                 DESTINATION "lib/swift_static/${arch_subdir}"
+                                 COMPONENT sdk-overlay)
+    endif()
+
+    swift_install_in_component(FILES "${musl_modulemap_out}"
+                               DESTINATION "lib/swift/${arch_subdir}"
+                               COMPONENT sdk-overlay)
+    swift_install_in_component(FILES "${musl_header_out}"
+                               DESTINATION "lib/swift/${arch_subdir}"
+                               COMPONENT sdk-overlay)
+  endforeach()
+endforeach()
+add_custom_target(musl_modulemap DEPENDS ${musl_modulemap_target_list})
+set_property(TARGET musl_modulemap PROPERTY FOLDER "Miscellaneous")
+add_dependencies(sdk-overlay musl_modulemap)
+
 set(glibc_modulemap_target_list)
 foreach(sdk ${SWIFT_SDKS})
   if(NOT "${sdk}" STREQUAL "LINUX" AND
@@ -238,7 +313,7 @@ foreach(sdk ${SWIFT_SDKS})
         FLAGS "-DCMAKE_SDK=${sdk}")
     list(APPEND glibc_modulemap_target_list ${glibc_header_target})
 
-    if(SWIFT_BUILD_STATIC_STDLIB)
+    if(SWIFT_BUILD_STATIC_STDLIB OR SWIFT_SDK_${sdk}_STATIC_ONLY)
       add_custom_command_target(
         copy_glibc_modulemap_header_static
         COMMAND
@@ -287,7 +362,7 @@ foreach(sdk ${SWIFT_SDKS})
                                DESTINATION "lib/swift/${arch_subdir}"
                                COMPONENT sdk-overlay)
 
-    if(SWIFT_BUILD_STATIC_STDLIB)
+    if(SWIFT_BUILD_STATIC_STDLIB OR SWIFT_SDK_${sdk}_STATIC_ONLY)
       swift_install_in_component(FILES "${glibc_modulemap_out}"
                                  DESTINATION "lib/swift_static/${arch_subdir}"
                                  COMPONENT sdk-overlay)
diff --git a/stdlib/public/Platform/Platform.swift b/stdlib/public/Platform/Platform.swift
index a3e8f439fe44c..0c2d63a0cffdb 100644
--- a/stdlib/public/Platform/Platform.swift
+++ b/stdlib/public/Platform/Platform.swift
@@ -344,7 +344,9 @@ public var SIG_IGN: sig_t { return unsafeBitCast(1, to: sig_t.self) }
 public var SIG_ERR: sig_t { return unsafeBitCast(-1, to: sig_t.self) }
 public var SIG_HOLD: sig_t { return unsafeBitCast(3, to: sig_t.self) }
 #elseif os(Linux) || os(FreeBSD) || os(PS4) || os(Android) || os(Haiku)
+#if !canImport(SwiftMusl)
 public typealias sighandler_t = __sighandler_t
+#endif
 
 public var SIG_DFL: sighandler_t? { return nil }
 public var SIG_IGN: sighandler_t {
@@ -487,7 +489,7 @@ extension Duration {
 public var environ: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?> {
   return _swift_stdlib_getEnviron()
 }
-#elseif os(Linux)
+#elseif os(Linux) && !canImport(SwiftMusl)
 public var environ: UnsafeMutablePointer<UnsafeMutablePointer<CChar>?> {
   return __environ
 }
diff --git a/stdlib/public/Platform/SwiftMusl.h b/stdlib/public/Platform/SwiftMusl.h
new file mode 100644
index 0000000000000..4605812b9d68c
--- /dev/null
+++ b/stdlib/public/Platform/SwiftMusl.h
@@ -0,0 +1,187 @@
+//===--- SwiftMusl.h ------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include <assert.h>
+#include <float.h>
+#include <iso646.h>
+#include <limits.h>
+#include <stdalign.h>
+#include <stdarg.h>
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <time.h>
+#include <tgmath.h>
+#include <complex.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fenv.h>
+#include <inttypes.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+#include <string.h>
+#include <threads.h>
+#include <uchar.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <aio.h>
+#include <arpa/inet.h>
+#include <arpa/ftp.h>
+#include <arpa/nameser.h>
+#include <arpa/nameser_compat.h>
+#include <arpa/telnet.h>
+#include <arpa/tftp.h>
+#include <cpio.h>
+#include <dirent.h>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <fmtmsg.h>
+#include <fnmatch.h>
+#include <ftw.h>
+#include <glob.h>
+#include <grp.h>
+#include <iconv.h>
+#include <langinfo.h>
+#include <libgen.h>
+#include <monetary.h>
+#include <mqueue.h>
+#include <net/if.h>
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+#include <net/route.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netinet/ether.h>
+#include <netinet/icmp6.h>
+#include <netinet/if_ether.h>
+#include <netinet/igmp.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/udp.h>
+#include <nl_types.h>
+#include <poll.h>
+#include <pthread.h>
+#include <pwd.h>
+#include <regex.h>
+#include <sched.h>
+#include <search.h>
+#include <semaphore.h>
+#include <spawn.h>
+#include <strings.h>
+#include <stropts.h>
+#include <sys/ipc.h>
+#include <sys/mman.h>
+#include <sys/msg.h>
+#include <sys/resource.h>
+#include <sys/select.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <sys/utsname.h>
+#include <sys/wait.h>
+#include <sys/acct.h>
+#include <sys/auxv.h>
+#include <sys/cachectl.h>
+#include <sys/dir.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <sys/fanotify.h>
+#include <sys/file.h>
+#include <sys/fsuid.h>
+#include <sys/inotify.h>
+#include <sys/ioctl.h>
+#include <sys/io.h>
+#include <sys/klog.h>
+#include <sys/membarrier.h>
+#include <sys/mount.h>
+#include <sys/mtio.h>
+#include <sys/param.h>
+#include <sys/personality.h>
+#include <sys/prctl.h>
+#include <sys/procfs.h>
+#include <sys/ptrace.h>
+#include <sys/quota.h>
+#include <sys/random.h>
+#include <sys/reboot.h>
+#include <sys/reg.h>
+#include <sys/sendfile.h>
+#include <sys/signalfd.h>
+#include <sys/statfs.h>
+#include <sys/stropts.h>
+#include <sys/swap.h>
+#include <sys/syscall.h>
+#include <sys/sysinfo.h>
+#include <sys/syslog.h>
+#include <sys/sysmacros.h>
+#include <sys/timeb.h>
+#include <sys/timerfd.h>
+#include <sys/timex.h>
+#include <sys/ttydefaults.h>
+#include <sys/ucontext.h>
+#include <sys/user.h>
+#include <sys/vfs.h>
+#include <sys/xattr.h>
+#include <syslog.h>
+#include <tar.h>
+#include <termios.h>
+#include <ucontext.h>
+#include <unistd.h>
+#include <ulimit.h>
+#include <utime.h>
+#include <utmpx.h>
+#include <alloca.h>
+#include <ar.h>
+#include <byteswap.h>
+#include <crypt.h>
+#include <elf.h>
+#include <endian.h>
+#include <err.h>
+#include <getopt.h>
+#include <ifaddrs.h>
+#include <lastlog.h>
+#include <libintl.h>
+#include <link.h>
+#include <malloc.h>
+#include <memory.h>
+#include <mntent.h>
+#include <netpacket/packet.h>
+#include <paths.h>
+#include <pty.h>
+#include <resolv.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/sg.h>
+#include <shadow.h>
+#include <stdio_ext.h>
+#include <syscall.h>
+#include <sysexits.h>
+#include <utmp.h>
+#include <values.h>
+#include <unwind.h>
+#include <wordexp.h>
+#include <fts.h>
diff --git a/stdlib/public/Platform/musl.modulemap b/stdlib/public/Platform/musl.modulemap
index 18fe29972c3e6..b7f0d67bc5bb4 100644
--- a/stdlib/public/Platform/musl.modulemap
+++ b/stdlib/public/Platform/musl.modulemap
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,102 +10,994 @@
 //
 //===----------------------------------------------------------------------===//
 
-module SwiftMusl [system] {
-  header "stdc-predef.h"
+// Note that this module map requires some changes to the Musl headers in order
+// for it to work.  Specifically:
+//
+// - The types need to be broken out of <bits/alltypes.h> into individual files
+//   in <bits/types>.
+//
+// - The definitions included in <bits/alltypes.h> need to be broken out into
+//   <bits/musldefs.h>.
+//
+// - A _modules directory needs to be created; for each of the files mentioned
+//   in _modules below there should be a header that looks like
+//
+//      #if !__building_module(stdc_foo)
+//      #error "Do not include this header directly, include <foo.h> instead"
+//      #endif
+//      #include <foo.h>
+//
+//   This is so that the replacement headers from Clang and Libc++ work as
+//   expected.
+
+module _musl [system] {
+  config_macros _GNU_SOURCE, _BSD_SOURCE, _XOPEN_SOURCE, _POSIX_SOURCE, _POSIX_C_SOURCE, _LARGEFILE64_SOURCE, _ALL_SOURCE, _DEFAULT_SOURCE, __STRICT_ANSI__
+
   header "features.h"
 
-  // C standard library
+  header "bits/musldefs.h"
+
+  exclude header "bits/alltypes.h"
+
+  // Type declarations live in bits
+  module types {
+    umbrella "bits/types"
+      module * {
+      export *
+    }
+  }
+}
+
+// Headers that can be overridden by Clang or libc++; in this case what we do is
+// we create an underscored module to wrap the actual header, then have the
+// module with the nicer name include a forwarding header from _modules.  This
+// ensures that e.g. `import float_h` will result in pulling in the Clang
+// or libc++ versions as expected.
+
+module _assert [system] {
+  textual header "assert.h"
+}
+module assert_h [system] {
+  header "_modules/assert_h.h"
+  export *
+}
+
+module _complex [system] {
   header "complex.h"
+  export *
+}
+module complex_h [system] {
+  header "_modules/complex_h.h"
+  export *
+}
+
+module _ctype [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "ctype.h"
+  export *
+}
+module ctype_h [system] {
+  header "_modules/ctype_h.h"
+  export *
+}
+
+module _errno [system] {
+  config_macros _GNU_SOURCE
   header "errno.h"
+  export *
+}
+module errno_h [system] {
+  header "_modules/errno_h.h"
+  export *
+}
+
+module _fenv [system] {
   header "fenv.h"
+  export *
+}
+module fenv_h [system] {
+  header "_modules/fenv_h.h"
+  export *
+}
+
+module _float [system] {
   header "float.h"
+  export *
+}
+module float_h [system] {
+  header "_modules/float_h.h"
+  export *
+}
+
+module _inttypes [system] {
   header "inttypes.h"
+  export *
+}
+module inttypes_h [system] {
+  header "_modules/inttypes_h.h"
+  use stdint_h
+  export *
+}
+
+module _iso646 [system] {
   header "iso646.h"
+  export *
+}
+module iso646_h [system] {
+  header "_modules/iso646_h.h"
+  export *
+}
+
+module _limits [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "limits.h"
+  export *
+}
+module limits_h [system] {
+  header "_modules/limits_h.h"
+  export *
+}
+
+module _locale [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "locale.h"
+  export *
+}
+module locale_h [system] {
+  header "_modules/locale_h.h"
+  export *
+}
+
+module _math [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _XOPEN_SOURCE
   header "math.h"
-  header "pty.h"
+  export *
+}
+module math_h [system] {
+  header "_modules/math_h.h"
+  export *
+}
+
+module _setjmp [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "setjmp.h"
-  header "signal.h"
+  export *
+}
+module setjmp_h [system] {
+  header "_modules/setjmp_h.h"
+  export *
+}
+
+module _stdalign [system] {
+  header "stdalign.h"
+  export *
+}
+module stdalign_h [system] {
+  header "_modules/stdalign_h.h"
+  export *
+}
+
+module _stdarg [system] {
   header "stdarg.h"
+  export *
+}
+module stdarg_h [system] {
+  header "_modules/stdarg_h.h"
+  export *
+}
+
+module _stdatomic [system] {
+  header "stdatomic.h"
+  export *
+}
+module stdatomic_h [system] {
+  header "_modules/stdatomic_h.h"
+  export *
+}
+
+module _stdbool [system] {
   header "stdbool.h"
+  export *
+}
+module stdbool_h [system] {
+  header "_modules/stdbool_h.h"
+  export *
+}
+
+module _stddef [system] {
   header "stddef.h"
+  export *
+}
+module stddef_h [system] {
+  header "_modules/stddef_h.h"
+  export *
+}
+
+module _stdint [system] {
   header "stdint.h"
+  export *
+}
+module stdint_h [system] {
+  header "_modules/stdint_h.h"
+  export *
+}
+
+module _stdio [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "stdio.h"
+  export *
+}
+module stdio_h [system] {
+  header "_modules/stdio_h.h"
+  export *
+}
+
+module _stdlib [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "stdlib.h"
+  export *
+}
+module stdlib_h [system] {
+  header "_modules/stdlib_h.h"
+  export *
+}
+
+module _string [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "string.h"
+  export *
+}
+module string_h [system] {
+  header "_modules/string_h.h"
+  export *
+}
+
+module _tgmath [system] {
   header "tgmath.h"
+  export *
+}
+module tgmath_h [system] {
+  header "_modules/tgmath_h.h"
+  export *
+}
+
+module _uchar [system] {
+  header "uchar.h"
+  export *
+}
+module uchar_h [system] {
+  header "_modules/uchar_h.h"
+  export *
+}
+
+module _wchar [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
+  header "wchar.h"
+  export *
+}
+module wchar_h [system] {
+  header "_modules/wchar_h.h"
+  export *
+}
+
+module _wctype [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
+  header "wctype.h"
+  export *
+}
+module wctype_h [system] {
+  header "_modules/wctype_h.h"
+  export *
+}
+
+// C library headers
+module time_h [system] {
+  config_macros _POSIX_SOURCE, _POSIX_C_SOURCE, _XOPEN_SOURCE, _GNU_SOURCE, _BSD_SOURCE
   header "time.h"
-  header "utmp.h"
+  export *
+}
+
+module signal_h [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
+  header "signal.h"
+  export *
+}
+
+module stdnoreturn_h [system] {
+  header "stdnoreturn.h"
+  export *
+}
+
+module threads_h [system] {
+  header "threads.h"
+  export *
+}
 
-  // POSIX
+// POSIX
+module posix_aio [system] {
+  config_macros _LARGEFILE64_SOURCE
   header "aio.h"
+  export *
+}
+
+module arpa_inet [system] {
   header "arpa/inet.h"
+  export *
+}
+
+// Non-POSIX
+module arpa_ftp [system] {
+  header "arpa/ftp.h"
+  export *
+}
+module arpa_nameser [system] {
+  header "arpa/nameser.h"
+  export *
+}
+module arpa_nameser_compat [system] {
+  header "arpa/nameser_compat.h"
+  export *
+}
+module arpa_telnet [system] {
+  header "arpa/telnet.h"
+  export *
+}
+module arpa_tftp [system] {
+  header "arpa/tftp.h"
+  export *
+}
+
+// POSIX
+module posix_cpio [system] {
   header "cpio.h"
+  export *
+}
+module posix_dirent [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE, _XOPEN_SOURCE
   header "dirent.h"
+  export *
+}
+module posix_dlfcn [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "dlfcn.h"
+  export *
+
+  link "dl"
+}
+module posix_fcntl [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "fcntl.h"
+  export *
+}
+module posix_fmtmsg [system] {
   header "fmtmsg.h"
+  export *
+}
+module posix_fnmatch [system] {
   header "fnmatch.h"
+  export *
+}
+module posix_ftw [system] {
+  config_macros _LARGEFILE64_SOURCE
   header "ftw.h"
+  export *
+}
+module posix_glob [system] {
+  config_macros _LARGEFILE64_SOURCE
   header "glob.h"
+  export *
+}
+module posix_grp [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _XOPEN_SOURCE
   header "grp.h"
+  export *
+}
+module posix_iconv [system] {
   header "iconv.h"
-  header "ifaddrs.h"
+  export *
+}
+module posix_langinfo [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "langinfo.h"
+  export *
+}
+module posix_libgen [system] {
   header "libgen.h"
-  header "link.h"
+  export *
+}
+module posix_monetary [system] {
   header "monetary.h"
+  export *
+}
+module posix_mqueue [system] {
+  header "mqueue.h"
+  export *
+}
+
+// POSIX
+module net_if [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "net/if.h"
+  export *
+}
+
+// Non-POSIX
+module fts [system] {
+  header "fts.h"
+  export *
+
+  link "fts"
+}
+
+module net_ethernet [system] {
+  header "net/ethernet.h"
+  // Include <netinet/if_ether.h> here because these two headers circularly
+  // depend on one another
+  header "netinet/if_ether.h"
+  export *
+}
+module net_if_arp [system] {
+  header "net/if_arp.h"
+  export *
+}
+module net_route [system] {
+  header "net/route.h"
+  export *
+}
+
+// POSIX
+module posix_netdb [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "netdb.h"
+  export *
+}
+
+// POSIX
+module netinet_in [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "netinet/in.h"
+  export *
+}
+module netinet_tcp [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "netinet/tcp.h"
+  export *
+}
+
+// Non-POSIX
+module netinet_ether [system] {
+  header "netinet/ether.h"
+  export *
+}
+module netinet_icmp6 [system] {
+  header "netinet/icmp6.h"
+  export *
+}
+// Can't have this one as a module because of the circular dependency
+// between netinet/if_ether.h and net/ethernet.h
+//
+// module netinet_if_ether [system] {
+//   header "netinet/if_ether.h"
+//   export *
+// }
+module netinet_igmp [system] {
+  header "netinet/igmp.h"
+  export *
+}
+module netinet_in_systm [system] {
+  header "netinet/in_systm.h"
+  export *
+}
+module netinet_ip [system] {
+  header "netinet/ip.h"
+  export *
+}
+module netinet_ip6 [system] {
+  header "netinet/ip6.h"
+  export *
+}
+module netinet_ip_icmp [system] {
+  header "netinet/ip_icmp.h"
+  export *
+}
+module netinet_udp [system] {
+  config_macros _GNU_SOURCE
+  header "netinet/udp.h"
+  export *
+}
+
+// POSIX
+module posix_nl_types [system] {
   header "nl_types.h"
+  export *
+}
+module posix_poll [system] {
+  config_macros _GNU_SOURCE
   header "poll.h"
+  export *
+}
+module posix_pthread [system] {
+  config_macros _GNU_SOURCE
   header "pthread.h"
+  export *
+
+  link "pthread"
+}
+module posix_pwd [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _XOPEN_SOURCE
   header "pwd.h"
+  export *
+}
+module posix_regex [system] {
   header "regex.h"
+  export *
+}
+module posix_sched [system] {
+  config_macros _GNU_SOURCE
   header "sched.h"
+  export *
+}
+module posix_search [system] {
+  config_macros _GNU_SOURCE
   header "search.h"
+  export *
+}
+module posix_semaphore [system] {
   header "semaphore.h"
+  export *
+}
+module posix_spawn [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "spawn.h"
+  export *
+}
+module posix_strings [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "strings.h"
-  header "sys/file.h"
-  header "sys/inotify.h"
-  header "sys/ioctl.h"
+  export *
+}
+module posix_stropts [system] {
+  header "stropts.h"
+  export *
+}
+
+// POSIX
+module sys_ipc [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "sys/ipc.h"
+  export *
+}
+module sys_mman [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE
   header "sys/mman.h"
-  header "sys/mount.h"
+  export *
+}
+module sys_msg [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "sys/msg.h"
+  export *
+}
+module sys_resource [system] {
+  config_macros _GNU_SOURCE, _LARGEFILE64_SOURCE
   header "sys/resource.h"
+  export *
+}
+module sys_select [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "sys/select.h"
+  export *
+}
+module sys_sem [system] {
+  config_macros _GNU_SOURCE
   header "sys/sem.h"
-  header "sys/sendfile.h"
+  export *
+}
+module sys_shm [system] {
+  config_macros _GNU_SOURCE
   header "sys/shm.h"
+  export *
+}
+module sys_socket [system] {
+  config_macros _GNU_SOURCE
   header "sys/socket.h"
+  export *
+}
+module sys_stat [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE, _XOPEN_SOURCE
   header "sys/stat.h"
+  export *
+}
+module sys_statvfs [system] {
+  config_macros _LARGEFILE64_SOURCE
   header "sys/statvfs.h"
+  export *
+}
+module sys_time [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "sys/time.h"
+  export *
+}
+module sys_times [system] {
   header "sys/times.h"
+  export *
+}
+module sys_types [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE
   header "sys/types.h"
+  export *
+}
+module sys_uio [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE
   header "sys/uio.h"
+  export *
+}
+module sys_un [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "sys/un.h"
-  header "sys/user.h"
+  export *
+}
+module sys_utsname [system] {
+  config_macros _GNU_SOURCE
   header "sys/utsname.h"
+  export *
+}
+module sys_wait [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _POSIX_C_SOURCE, _POSIX_SOURCE, _XOPEN_SOURCE
   header "sys/wait.h"
-  header "sysexits.h"
+  export *
+}
+
+// Non-POSIX
+module sys_acct [system] {
+  header "sys/acct.h"
+  export *
+}
+module sys_auxv [system] {
+  header "sys/auxv.h"
+  export *
+}
+module sys_cachectl [system] {
+  header "sys/cachectl.h"
+  export *
+}
+module sys_dir [system] {
+  header "sys/dir.h"
+  export *
+}
+module sys_epoll [system] {
+  header "sys/epoll.h"
+  export *
+}
+module sys_eventfd [system] {
+  header "sys/eventfd.h"
+  export *
+}
+module sys_fanotify [system] {
+  header "sys/fanotify.h"
+  export *
+}
+module sys_file [system] {
+  header "sys/file.h"
+  export *
+}
+module sys_fsuid [system] {
+  header "sys/fsuid.h"
+  export *
+}
+module sys_inotify [system] {
+  header "sys/inotify.h"
+  export *
+}
+module sys_ioctl [system] {
+  header "sys/ioctl.h"
+  export *
+}
+module sys_io [system] {
+  header "sys/io.h"
+  export *
+}
+module sys_klog [system] {
+  header "sys/klog.h"
+  export *
+}
+module sys_membarrier [system] {
+  header "sys/membarrier.h"
+  export *
+}
+module sys_mount [system] {
+  header "sys/mount.h"
+  export *
+}
+module sys_mtio [system] {
+  header "sys/mtio.h"
+  export *
+}
+module sys_param [system] {
+  header "sys/param.h"
+  export *
+}
+module sys_personality [system] {
+  header "sys/personality.h"
+  export *
+}
+module sys_prctl [system] {
+  header "sys/prctl.h"
+  export *
+}
+module sys_procfs [system] {
+  header "sys/procfs.h"
+  export *
+}
+module sys_ptrace [system] {
+  header "sys/ptrace.h"
+  export *
+}
+module sys_quota [system] {
+  header "sys/quota.h"
+  export *
+}
+module sys_random [system] {
+  header "sys/random.h"
+  export *
+}
+module sys_reboot [system] {
+  header "sys/reboot.h"
+  export *
+}
+module sys_reg [system] {
+  header "sys/reg.h"
+  export *
+}
+module sys_sendfile [system] {
+  config_macros _LARGEFILE64_SOURCE
+  header "sys/sendfile.h"
+  export *
+}
+module sys_signalfd [system] {
+  header "sys/signalfd.h"
+  export *
+}
+module sys_statfs [system] {
+  config_macros _LARGEFILE64_SOURCE
+  header "sys/statfs.h"
+  export *
+}
+module sys_stropts [system] {
+  header "sys/stropts.h"
+  export *
+}
+module sys_swap [system] {
+  header "sys/swap.h"
+  export *
+}
+module sys_syscall [system] {
+  header "sys/syscall.h"
+  export *
+}
+module sys_sysinfo [system] {
+  header "sys/sysinfo.h"
+  export *
+}
+module sys_syslog [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
+  header "sys/syslog.h"
+  export *
+}
+module sys_sysmacros [system] {
+  header "sys/sysmacros.h"
+  export *
+}
+module sys_timeb [system] {
+  header "sys/timeb.h"
+  export *
+}
+module sys_timerfd [system] {
+  header "sys/timerfd.h"
+  export *
+}
+module sys_timex [system] {
+  header "sys/timex.h"
+  export *
+}
+module sys_ttydefaults [system] {
+  header "sys/ttydefaults.h"
+  export *
+}
+module sys_ucontext [system] {
+  config_macros _GNU_SOURCE, _BSD_SOURCE
+  header "sys/ucontext.h"
+  export *
+}
+module sys_user [system] {
+  header "sys/user.h"
+  export *
+}
+module sys_vfs [system] {
+  header "sys/vfs.h"
+  export *
+}
+module sys_xattr [system] {
+  header "sys/xattr.h"
+  export *
+}
+
+// POSIX
+module posix_syslog [system] {
   header "syslog.h"
+  export *
+}
+module posix_tar [system] {
   header "tar.h"
+  export *
+}
+module posix_termios [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "termios.h"
-  header "ulimit.h"
+  export *
+}
+module posix_ucontext [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
+  header "ucontext.h"
+  export *
+}
+module posix_unistd [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE, _LARGEFILE64_SOURCE, _XOPEN_SOURCE
   header "unistd.h"
+  export *
+}
+module posix_ulimit [system] {
+  header "ulimit.h"
+  export *
+}
+module posix_utime [system] {
   header "utime.h"
+  export *
+}
+module posix_utmpx [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
   header "utmpx.h"
+  export *
+}
+
+// Other, non-standard headers
+module linux_alloca [system] {
+  header "alloca.h"
+  export *
+}
+module linux_ar [system] {
+  header "ar.h"
+  export *
+}
+module linux_byteswap [system] {
+  header "byteswap.h"
+  export *
+}
+module linux_crypt [system] {
+  header "crypt.h"
+  export *
+}
+module linux_elf [system] {
+  header "elf.h"
+  export *
+}
+module linux_endian [system] {
+  config_macros _BSD_SOURCE, _GNU_SOURCE
+  header "endian.h"
+  export *
+}
+module linux_err [system] {
+  header "err.h"
+  export *
+}
+module linux_getopt [system] {
+  header "getopt.h"
+  export *
+}
+module linux_ifaddrs [system] {
+  header "ifaddrs.h"
+  export *
+}
+module linux_lastlog [system] {
+  header "lastlog.h"
+  export *
+}
+module linux_libintl [system] {
+  header "libintl.h"
+  export *
+}
+module linux_link [system] {
+  header "link.h"
+  export *
+}
+module linux_malloc [system] {
+  header "malloc.h"
+  export *
+}
+module linux_memory [system] {
+  header "memory.h"
+  export *
+}
+module linux_mntent [system] {
+  header "mntent.h"
+  export *
+}
+module linux_netpacket [system] {
+  header "netpacket/packet.h"
+  export *
+}
+module linux_paths [system] {
+  header "paths.h"
+  export *
+}
+module linux_pty [system] {
+  header "pty.h"
+  export *
+}
+module linux_resolv [system] {
+  header "resolv.h"
+  export *
+
+  link "resolv"
+}
+module linux_scsi [system] {
+  header "scsi/scsi.h"
+  header "scsi/scsi_ioctl.h"
+  header "scsi/sg.h"
+  export *
+}
+module linux_shadow [system] {
+  header "shadow.h"
+  export *
+}
+module linux_stdio_ext [system] {
+  header "stdio_ext.h"
+  export *
+}
+module linux_syscall [system] {
+  header "syscall.h"
+  export *
+}
+module linux_sysexits [system] {
+  header "sysexits.h"
+  export *
+}
+module linux_utmp [system] {
+  header "utmp.h"
+  export *
+}
+module linux_values [system] {
+  header "values.h"
+  export *
+}
+module linux_unwind [system] {
+  header "unwind.h"
+  export *
+}
+module linux_wordexp [system] {
   header "wordexp.h"
+  export *
+}
 
-  // <assert.h>'s use of NDEBUG requires textual inclusion. 
-  textual header "assert.h"
+module linux_excludes [system] {
+  // Linux redirection headers
+  exclude header "sys/kd.h"
+  exclude header "sys/soundcard.h"
+  exclude header "sys/vt.h"
+
+  // Redirection headers
+  exclude header "sys/termios.h"
+  exclude header "sys/fcntl.h"
+  exclude header "sys/errno.h"
+  exclude header "sys/poll.h"
+  exclude header "sys/signal.h"
 
+  exclude header "wait.h"
+}
+
+// START SWIFT ONLY
+// This is for Swift; it includes all the (modular) Musl headers
+module SwiftMusl [system] {
+  header "SwiftMusl.h"
   export *
 }
+// END SWIFT ONLY