sys_time: avoid compiler warnings sys/time uses #if/#else/#endif, and is therefore not subject to the gcc optimization. The #pragma GCC system_header must occur up front. * lib/sys_time.in.h (includes): Ensure gcc pragma is unconditional, fixing regression from 2010-03-29. Reported by Simon Josefsson. Signed-off-by: Eric Blake <eblake@redhat.com>