Use the FSF m4 instead of the BSD m4, because the BSD m4 is reporting problems
processing config.c.in.

--- Makefile.in	Mon Aug 18 14:52:43 1997
+++ Makefile.in	Tue Aug 26 14:14:44 1997
@@ -68,7 +68,7 @@
 HOST_PREFIX_1 = loser-
 
 # These flag values are normally overridden by the configure script.
-CFLAGS = -g
+CFLAGS+= -g
 CXXFLAGS = -g -O2
 
 LIBCFLAGS = $(CFLAGS)
@@ -121,7 +121,7 @@
 
 M4 = `if [ -f $$r/m4/m4 ] ; \
 	then echo $$r/m4/m4 ; \
-	else echo m4 ; fi`
+	else echo gm4 ; fi`
 
 MAKEINFO = `if [ -f $$r/texinfo/makeinfo/Makefile ] ; \
 	then echo $$r/texinfo/makeinfo/makeinfo ; \

The top level Makefile overrides the use of BISON to just "bison" instead
of bison -y, so use YACC, since that's what we're trying to define anyway.

--- gnats/Makefile.in	Mon Aug 18 14:52:44 1997
+++ gnats/Makefile.in	Tue Aug 26 14:45:55 1997
@@ -118,7 +118,7 @@
 # Set RANLIB = echo if your system doesn't have or need ranlib.
 RANLIB = @RANLIB@
 
-BISON = @YACC@
+YACC = @YACC@
 DIFFOPT = @DIFFOPT@
 
 # These are set by autoconf.
@@ -435,7 +435,7 @@
 
 getdate.c: getdate.y
 	@echo expect 10 shift/reduce conflicts
-	$(BISON) -d $(srcdir)/getdate.y
+	$(YACC) -d $(srcdir)/getdate.y
 	mv y.tab.c getdate.c
 	mv y.tab.h getdate.h