Fix for SunOS 4 builds.

dbm/include/mcom_db.h

@@ -72,8 +72,7 @@
 #define BIG_ENDIAN      4321
 #define LITTLE_ENDIAN   1234            /* LSB first: i386, vax, all NT risc */
 
-#if !defined(SVR4) && !defined(__svr4__) && !defined(__SVR4)
-/* compat.h is only in 4.1.3 machines. - dp */
+#ifdef HAVE_COMPAT_H
 #include <compat.h>
 #endif