Compilation regression in musl libc in Emscripten 4.0.0

[hoodmane]

A compilation regression in 4.0.0

Version of emscripten/emsdk

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 4.0.0 (97c7c2adab1791b9487d1f376934a3bdc28f8a67)
Copyright (C) 2014 the Emscripten authors (see AUTHORS.txt)
This is free and open source software under the MIT license.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

a.cpp

#include <xlocale.h> 
#include <map>

Compilation command

em++ -c a.cpp

Output

In file included from a.cpp:3:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/map:2175:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/functional:552:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__functional/boyer_moore_searcher.h:27:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/vector:325:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__format/formatter_bool.h:19:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__format/formatter_integral.h:35:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale:14:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api.h:27:
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api/musl.h:23:8: error: cannot add 'abi_tag' attribute in a redeclaration
   23 | inline _LIBCPP_HIDE_FROM_ABI long long strtoll_l(const char* __nptr, char** __endptr, int __base, locale_t) {
      |        ^
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__config:545:22: note: expanded from macro '_LIBCPP_HIDE_FROM_ABI'
  545 |       __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
      |                      ^
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/compat/xlocale.h:13:11: note: previous declaration is here
   13 | long long strtoll_l(const char *start, char **end, int base, locale_t loc);
      |           ^
In file included from a.cpp:3:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/map:2175:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/functional:552:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__functional/boyer_moore_searcher.h:27:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/vector:325:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__format/formatter_bool.h:19:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__format/formatter_integral.h:35:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale:14:
In file included from /home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api.h:27:
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__locale_dir/locale_base_api/musl.h:27:8: error: cannot add 'abi_tag' attribute in a redeclaration
   27 | inline _LIBCPP_HIDE_FROM_ABI unsigned long long strtoull_l(const char* __nptr, char** __endptr, int __base, locale_t) {
      |        ^
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/c++/v1/__config:545:22: note: expanded from macro '_LIBCPP_HIDE_FROM_ABI'
  545 |       __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
      |                      ^
/home/rchatham/Documents/programming/pyodide/emsdk/emsdk/upstream/emscripten/cache/sysroot/include/compat/xlocale.h:14:20: note: previous declaration is here
   14 | unsigned long long strtoull_l(const char *start, char **end, int base, locale_t loc);
      |                    ^
2 errors generated.

[sbc100]

I think this was already reported in #23413 which was fixed in #23414 and releases in 4.0.1.

[hoodmane]

Sorry for the duplicate.