[libc++][C++03] Remove some of the C++03-specific C wrapper headers (#163772)

`include_next` doesn't work very well with the C++03 headers and
modules. Since these specific headers are very self-contained there
isn't much of a reason to split them into C++03/non-C++03 headers, so
let's just remove them. The few C wrapper headers that aren't as
self-contained will be refactored in a separate patch.

Author: philnik777

libcxx/include/CMakeLists.txt

@@ -1593,7 +1593,6 @@ set(files
   __cxx03/cmath
   __cxx03/codecvt
   __cxx03/complex
-  __cxx03/complex.h
   __cxx03/condition_variable
   __cxx03/csetjmp
   __cxx03/csignal
@@ -1606,25 +1605,20 @@ set(files
   __cxx03/cstring
   __cxx03/ctgmath
   __cxx03/ctime
-  __cxx03/ctype.h
   __cxx03/cuchar
   __cxx03/cwchar
   __cxx03/cwctype
   __cxx03/deque
-  __cxx03/errno.h
   __cxx03/exception
   __cxx03/experimental/__config
   __cxx03/experimental/utility
   __cxx03/ext/__hash
   __cxx03/ext/hash_map
   __cxx03/ext/hash_set
-  __cxx03/fenv.h
-  __cxx03/float.h
   __cxx03/forward_list
   __cxx03/fstream
   __cxx03/functional
   __cxx03/future
-  __cxx03/inttypes.h
   __cxx03/iomanip
   __cxx03/ios
   __cxx03/iosfwd
@@ -1651,19 +1645,15 @@ set(files
   __cxx03/sstream
   __cxx03/stack
   __cxx03/stdatomic.h
-  __cxx03/stdbool.h
-  __cxx03/stddef.h
   __cxx03/stdexcept
   __cxx03/stdint.h
-  __cxx03/stdio.h
   __cxx03/stdlib.h
   __cxx03/streambuf
   __cxx03/string
   __cxx03/string.h
   __cxx03/string_view
   __cxx03/strstream
   __cxx03/system_error
-  __cxx03/tgmath.h
   __cxx03/thread
   __cxx03/type_traits
   __cxx03/typeindex
@@ -1676,7 +1666,6 @@ set(files
   __cxx03/vector
   __cxx03/version
   __cxx03/wchar.h
-  __cxx03/wctype.h
   )
 
 configure_file("__config_site.in" "${LIBCXX_GENERATED_INCLUDE_TARGET_DIR}/__config_site" @ONLY)

libcxx/include/__cxx03/__thread/support/pthread.h

@@ -14,7 +14,7 @@
 #include <__cxx03/__chrono/duration.h>
 #include <__cxx03/__config>
 #include <__cxx03/ctime>
-#include <__cxx03/errno.h>
+#include <errno.h>
 #include <pthread.h>
 #include <sched.h>
 

libcxx/include/__cxx03/cctype

@@ -36,9 +36,9 @@ int toupper(int c);
 
 #include <__cxx03/__config>
 
-#include <__cxx03/ctype.h>
+#include <ctype.h>
 
-#ifndef _LIBCPP___CXX03_CTYPE_H
+#ifndef _LIBCPP_CTYPE_H
 #   error <cctype> tried including <ctype.h> but didn't find libc++'s <ctype.h> header. \
           This usually means that your header search paths are not configured properly.  \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/cerrno

@@ -24,9 +24,9 @@ Macros:
 
 #include <__cxx03/__config>
 
-#include <__cxx03/errno.h>
+#include <errno.h>
 
-#ifndef _LIBCPP___CXX03_ERRNO_H
+#ifndef _LIBCPP_ERRNO_H
 #   error <cerrno> tried including <errno.h> but didn't find libc++'s <errno.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/cfenv

@@ -54,9 +54,9 @@ int feupdateenv(const fenv_t* envp);
 
 #include <__cxx03/__config>
 
-#include <__cxx03/fenv.h>
+#include <fenv.h>
 
-#ifndef _LIBCPP___CXX03_FENV_H
+#ifndef _LIBCPP_FENV_H
 #   error <cfenv> tried including <fenv.h> but didn't find libc++'s <fenv.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/cfloat

@@ -71,9 +71,9 @@ Macros:
 
 #include <__cxx03/__config>
 
-#include <__cxx03/float.h>
+#include <float.h>
 
-#ifndef _LIBCPP___CXX03_FLOAT_H
+#ifndef _LIBCPP_FLOAT_H
 #   error <cfloat> tried including <float.h> but didn't find libc++'s <float.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/cinttypes

@@ -241,9 +241,9 @@ uintmax_t wcstoumax(const wchar_t* restrict nptr, wchar_t** restrict endptr, int
 // [cinttypes.syn]
 #include <__cxx03/cstdint>
 
-#include <__cxx03/inttypes.h>
+#include <inttypes.h>
 
-#ifndef _LIBCPP___CXX03_INTTYPES_H
+#ifndef _LIBCPP_INTTYPES_H
 #   error <cinttypes> tried including <inttypes.h> but didn't find libc++'s <inttypes.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/complex.h

@@ -39,9 +39,9 @@ Types:
 #include <__cxx03/__type_traits/is_integral.h>
 #include <__cxx03/version>
 
-#include <__cxx03/stddef.h>
+#include <stddef.h>
 
-#ifndef _LIBCPP___CXX03_STDDEF_H
+#ifndef _LIBCPP_STDDEF_H
 #   error <cstddef> tried including <stddef.h> but didn't find libc++'s <stddef.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \

libcxx/include/__cxx03/cstddef

@@ -97,9 +97,9 @@ void perror(const char* s);
 
 #include <__cxx03/__config>
 
-#include <__cxx03/stdio.h>
+#include <stdio.h>
 
-#ifndef _LIBCPP___CXX03_STDIO_H
+#ifndef _LIBCPP_STDIO_H
 #   error <cstdio> tried including <stdio.h> but didn't find libc++'s <stdio.h> header. \
           This usually means that your header search paths are not configured properly. \
           The header search paths should contain the C++ Standard Library headers before \