Fix 1993/jonth/Makefile about compilers

I got the entry to compile quite a while back (Yusuke Endoh fixed the X
code) but I never removed the comment saying that the entry might have
problems with modern compilers.

1993/jonth/Makefile

@@ -131,7 +131,6 @@ all: data ${TARGET}
 	supernova deep_magic magic charon pluto
 
 ${PROG}: ${PROG}.tmp.c
-	@echo "NOTE: This entry might not compile when using modern compilers."
 	${CC} ${CFLAGS} $< -o $@ ${LIBS}
 
 ${PROG}.tmp.c: ${PROG}.c