To avoid linking against shared libomp.so.

--- a/config.m4
+++ b/config.m4
@@ -62,6 +62,7 @@
 
   AC_MSG_CHECKING(omp_pause_resource_all usability)
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+    #error
     #include <omp.h>
   ]],[[
     omp_pause_resource_all(omp_pause_hard);
