Fixes the following compile error, present when the SHA1 library is libgcrypt:
CCLD glsl/tests/cache-test
glsl/.libs/libglsl.a(libmesautil_la-mesa-sha1.o): In function `call_once':
/mesa/src/util/../../include/c11/threads_posix.h:96: undefined reference to `pthread_once'
Signed-off-by: Rhys Kidd <rhyskidd@gmail.com>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>