/* #define SYSTEM_MALLOC */
/* MAKING_MAKEFILE must be defined in "ymakefile" before including config.h */
-#ifndef THIS_IS_YMAKEFILE
+#ifndef NOT_C_CODE
/* Make sure signal.h is included so macros below don't mess with it. */
/* DG/UX include files prevent multiple inclusion. */
extern struct sigaction act, oact;
#define signal(SIG,FUNC) berk_signal(SIG,FUNC)
-#else /* THIS_IS_YMAKEFILE */
-/* force gcc to be used */
-CC=gcc
-#endif /* not THIS_IS_YMAKEFILE */
+#endif /* not NOT_C_CODE */
+
+#ifndef __GNUC__
+#error You must use GCC to compiler Emascs on DGUX
+#endif
#define ORDINARY_LINK
#define START_FILES pre-crt0.o