Hardcode define MAJOREXECVERSION to MODVERSION

src/doomdef.h

@@ -216,13 +216,13 @@ extern FILE *logstream;
 // Note that we use this to help keep internal testing in check; this is why v2.1.0 is not version "1".
 #define MODVERSION 27
 
-// To version config.cfg, set MAJOREXECVERSION equal to MODVERSION
-// and increment SUBEXECVERSION whenever a config change is needed
+// To version config.cfg, MAJOREXECVERSION is set equal to MODVERSION automatically.
+// Increment SUBEXECVERSION whenever a config change is needed
 // that does not correspond to an increment in MODVERSION.
 // If MAJOREXECVERSION increases, set MINOREXECVERSION to 0.
-#define MAJOREXECVERSION 27
+#define MAJOREXECVERSION MODVERSION
 #define MINOREXECVERSION 0
-// (It would have been nice to use VERSION and SUBVERSION but those are different for DEVELOP builds)
+// (It would have been nice to use VERSION and SUBVERSION but those are zero'd out for DEVELOP builds)
 
 // Macros
 #define GETMAJOREXECVERSION(v) (v & 0xFFFF)