build: Add declaration checks to check for required syscall flags

The required flags are relatively new and some older enterprise
distributions do not feature them.

https://bugs.freedesktop.org/show_bug.cgi?id=63360

configure.ac

@@ -39,6 +39,15 @@ AC_CHECK_FUNC([dlopen], [],
               AC_CHECK_LIB([dl], [dlopen], DLOPEN_LIBS="-ldl"))
 AC_SUBST(DLOPEN_LIBS)
 
+AC_CHECK_DECL(SFD_CLOEXEC,[],
+	      [AC_MSG_ERROR("SFD_CLOEXEC is needed to compile weston")],
+	      [[#include <sys/signalfd.h>]])
+AC_CHECK_DECL(TFD_CLOEXEC,[],
+	      [AC_MSG_ERROR("TFD_CLOEXEC is needed to compile weston")],
+	      [[#include <sys/timerfd.h>]])
+AC_CHECK_DECL(CLOCK_MONOTONIC,[],
+	      [AC_MSG_ERROR("CLOCK_MONOTONIC is needed to compile weston")],
+	      [[#include <time.h>]])
 AC_CHECK_HEADERS([execinfo.h])
 
 AC_CHECK_FUNCS([mkostemp strchrnul])