[libc++] Avoids using ENODATA. (#86165)

This macro is deprecated in C++26.

Fixes #81360

---------

Co-authored-by: Louis Dionne <[email protected]>

Author: mordante

libcxx/docs/ReleaseNotes/19.rst

@@ -117,7 +117,10 @@ TODO
 
 ABI Affecting Changes
 ---------------------
-TODO
+
+- The optional POSIX macro ``ENODATA`` has been deprecated in C++ and POSIX 2017. The
+  ``random_device`` could throw a ``system_error`` with this value. It now
+  throws ``ENOMSG``.
 
 
 Build System Changes

libcxx/src/random.cpp

@@ -79,10 +79,8 @@ unsigned random_device::operator()() {
   char* p  = reinterpret_cast<char*>(&r);
   while (n > 0) {
     ssize_t s = read(__f_, p, n);
-    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     if (s == 0)
-      __throw_system_error(ENODATA, "random_device got EOF"); // TODO ENODATA -> ENOMSG
-    _LIBCPP_SUPPRESS_DEPRECATED_POP
+      __throw_system_error(ENOMSG, "random_device got EOF");
     if (s == -1) {
       if (errno != EINTR)
         __throw_system_error(errno, "random_device got an unexpected error");