[patch,libgfortran] Fix configure test for weakref support

[Richard Biener]

On Fri, Aug 28, 2015 at 10:07 AM, FX <fxcoudert@gmail.com> wrote:
> ping**2
>
> Given that it’s a configury-patch, I think what it needs is real exposure on unusual targets more than formal review, so I intend to commit it in 48 hours unless someone objects in the meantime. Then I’ll be around to fix things if some fall apart…

I think this breaks x86_64-linux where now all gfortran tests fail with sth like

spawn /home/abuild/rguenther/obj/gcc/testsuite/gfortran/../../gfortran
-B/home/abuild/rguenther/obj/gcc/testsuite/gfortran/../../
-B/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libgfortran/
/space/rguenther/src/svn/trunk2/gcc/testsuite/gfortran.dg/argument_checking_8.f90
-fno-diagnostics-show-caret -fdiagnostics-color=never -O3
-fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer
-finline-functions -pedantic-errors
-B/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libgfortran/.libs
-L/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libgfortran/.libs
-L/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libgfortran/.libs
-L/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libatomic/.libs
-B/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libquadmath/.libs
-L/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libquadmath/.libs
-L/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libquadmath/.libs
-lm -o ./argument_checking_8.exe^M
/home/abuild/rguenther/obj/x86_64-pc-linux-gnu/./libgfortran/.libs/libgfortran.so:
undefined reference to `pthread_mutex_trylock'^M
collect2: error: ld returned 1 exit status^M
compiler exited with status 1

Richard.

> FX
>
>
>
>
>> Le 14 août 2015 à 17:06, FX <fxcoudert@gmail.com> a écrit :
>>
>> This patch fixes PR 47571 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47571) by providing an adequate configure check (with AC_LINK_IFELSE) for weakref (which we use in intrinsics/system_clock.c).
>>
>> Tested by building libgfortran on x86_64-pc-linux-gnu, where SUPPORTS_WEAKREF gets defined to 1 as it should, and x86_64-apple-darwin14, where SUPPORTS_WEAKREF gets defined to 0 as it should. Then regtested on both targets.
>>
>> OK to commit to trunk?
>>
>> FX
>