On Fri, Feb 05, 2021 at 03:46:42PM +0100, Mark Wielaard wrote: > On Tue, 2021-02-02 at 05:56 +0300, Dmitry V. Levin wrote: > > On Mon, Feb 01, 2021 at 09:16:56PM -0300, Érico Nogueira via Elfutils-devel > > wrote: > > [...] > > > I'm not sure if it's a bug in this configure.ac or this macro, but > > > _GNU_SOURCE wasn't defined and lead to XSI strerror_r being used on > > > glibc until I added the trick with CFLAGS and old_CFLAGS. It's still way > > > slimmer than the previous version :) > > > > > > I see that -D_GNU_SOURCE is passed to the build via config/eu.am, maybe > > > it could somehow be plugged into configure.ac earlier? I'm not entirely > > > sure what's best. > > > > I wonder why don't we just use AC_USE_SYSTEM_EXTENSIONS > > instead of all these dances with -D_GNU_SOURCE. > > Probably because it was only introduced in autoconf 2.60 and we didn't > require that till 2009. We could now use it. But we'll have to be > careful to keep supporting BAD_FTS: > > dnl Older glibc had a broken fts that didn't work with Large File Systems. > dnl We want the version that can handler LFS, but include workaround if we > dnl get a bad one. Add define to CFLAGS (not AC_DEFINE it) since we need to > dnl check it before including config.h (which might define _FILE_OFFSET_BITS). > > I am not sure how AC_USE_SYSTEM_EXTENSIONS would interact with this and > config.h inclusion.
Well, AC_USE_SYSTEM_EXTENSIONS != AC_SYS_LARGEFILE, the latter indeed wouldn't work with old glibc, but the former has nothing to do with it. -- ldv
