VxWorks does not mark abort() or exit() noreturn

modules/libcom/src/osi/compiler/gcc/compilerSpecific.h

@@ -63,7 +63,10 @@
 /*
  * Unused marker
  */
+#ifndef vxWorks
+// VxWorks does not mark abort() or exit() noreturn!
 #define EPICS_UNUSED __attribute__((unused))
+#endif
 
 /*
  * No return marker