Current master doesn't build on Win10

[Arash Esbati]

Hi all,

current master (commit f7a2ff3b) doesn't build with Msys2.  The message
is:

--8<---------------cut here---------------start------------->8---
make[1]: Entering directory '/z/pathto/emacs/lib-src'
  CC       ntlib.o
  RC       emacsclient.res
  CC       pop.o
In file included from 
z:/pathto/msys64/mingw64/x86_64-w64-mingw32/include/guiddef.h:154,
                 from 
z:/pathto/msys64/mingw64/x86_64-w64-mingw32/include/winnt.h:635,
                 from 
z:/pathto/msys64/mingw64/x86_64-w64-mingw32/include/minwindef.h:163,
                 from 
z:/pathto/msys64/mingw64/x86_64-w64-mingw32/include/windef.h:9,
                 from 
z:/pathto/msys64/mingw64/x86_64-w64-mingw32/include/windows.h:69,
                 from ntlib.c:23:
../lib/string.h:965:1: error: expected ',' or ';' before '_GL_ATTRIBUTE_MALLOC'
  965 | _GL_FUNCDECL_SYS (strdup, char *,
      | ^~~~~~~~~~~~~~~~
make[1]: *** [Makefile:418: ntlib.o] Error 1
make[1]: Leaving directory '/z/pathto/emacs/lib-src'
--8<---------------cut here---------------end--------------->8---

I'm not sure this is an Emacs issue or not.  GCC 11.2 landed also today
on my HD.  Can others reproduce this?

Best, Arash