[Bug libfortran/48664] Use autoconf test instead of target blacklist to determine weak undefined reference support

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48664

--- Comment #3 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
The commit message went to PR47571 instead of this one:

Author: fxcoudert
Date: Mon Aug 31 10:37:30 2015
New Revision: 227335

URL: https://gcc.gnu.org/viewcvs?rev=227335&root=gcc&view=rev
Log:
        PR libfortran/47571
        * acinclude.m4 (LIBGFOR_GTHREAD_WEAK): Remove.
        (LIBGFOR_CHECK_WEAKREF): New test.
        * configure.ac: Call LIBGFOR_CHECK_WEAKREF instead of
        LIBGFOR_GTHREAD_WEAK.
        * config.h.in: Regenerate.
        * configure: Regenerate.
        * intrinsics/system_clock.c: Use SUPPORTS_WEAKREF instead of
        SUPPORTS_WEAK and GTHREAD_USE_WEAK.

Modified:
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/acinclude.m4
    trunk/libgfortran/config.h.in
    trunk/libgfortran/configure
    trunk/libgfortran/configure.ac
    trunk/libgfortran/intrinsics/system_clock.c