Reword alt code suggestion in 1993/cmills

It is perhaps ironic, however, that we have managed to do this given
that in multiple platforms it only shows a blank screen (the original
too). This has been noted in bugs.md should anyone wish to try and fix
it.

Add -Wno-implicit-int to Makefile.

1993/cmills/Makefile

@@ -38,7 +38,7 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-return-type -Wno-deprecated-non-prototype
+CSILENCE= -Wno-return-type -Wno-deprecated-non-prototype -Wno-implicit-int
 
 # Common C compiler warning flags
 #