[Bug c/86377] extern int errno; is treated as buggy function declaration [-Werror=strict-prototypes]

[um at mutluit dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86377

--- Comment #3 from U.Mutlu <um at mutluit dot com> ---
As said in the Remarks, the bug originally was triggered in this file in the
trunk:
../gcc_trunk/libiberty/pex-common.c:28

#include <errno.h>
#ifdef NEED_DECLARATION_ERRNO
extern int errno;
#endif