* m4/stdnoreturn.m4 (gl_STDNORETURN_H): Avoid problems with
bleeding-edge GCC that complains about 'int _Noreturn foo (void);'.
Problem reported by Jim Meyering in
<http://lists.gnu.org/archive/html/bug-gnulib/2012-08/msg00121.html>.
Also, rename the 'test' function to a void a clash with the
already-supplied 'main' function; this fixes a bug that incorrectly
rejected GCC 4.7.1's <stdnoreturn.h>.
* doc/posix-headers/stdnoreturn.texi (stdnoreturn.h):
Document GCC problem.
MSVC standard headers use __declspec(noreturn), so #define noreturn
to empty on that platform. Reported by Bruno Haible in
<http://lists.gnu.org/archive/html/bug-gnulib/2012-02/msg00152.html>.
* lib/stdnoreturn.in.h (noreturn): Define to empty on MSVC.
* doc/posix-headers/stdnoreturn.texi (stdnoreturn.h): Document this.