gnulib features.h? (was regex warnings)

[Paul Eggert]

Derek Price <address@hidden> writes:

> I'm seeing "warning: `pure' attribute directive ignored" warnings from
> regex_internal.h & regex_internal.c compiling with GCC 2.95.4 on Alpha
> Linux 2.2.20.  Similarly, I see "warning: `always_inline' attribute
> directive ignored" warnings compiling regcomp.c & regexec.c.
>
> Is this something worth working around or should I just ignore it?

I'd fix it if I were you.  You can use the __GNUC_PREREQ macro of
md5.h.

Come to think of it, perhaps gnulib should have a features.h include
file that substitutes for glibc's, when glibc is not the native C
library.  Then gnulib source files could include features.h
unconditionally, and this will remove the need for a lot of needless
differences from the GNU C library for __GNUC_PREREQ, __USE_GNU,
HAVE_FEATURES_H, and the like.

A downside of this approach is a possible version mismatch between a
native glibc features.h and the gnulib features.h.  But I expect we
could solve that problem if it actually arose.