===================================================================
RCS file: /cvs/mandoc/configure,v
retrieving revision 1.40
retrieving revision 1.42
diff -u -p -r1.40 -r1.42
--- mandoc/configure	2016/07/12 05:18:38	1.40
+++ mandoc/configure	2016/07/15 18:03:45	1.42
@@ -34,8 +34,9 @@ echo "config.log: writing..."
 MANPATH_DEFAULT="/usr/share/man:/usr/X11R6/man:/usr/local/man"
 OSNAME=
 
-CC=`printf "all:\\n\\t@echo \\\$(CC)\\n" | make -f -`
-CFLAGS="-g -W -Wall -Wstrict-prototypes -Wno-unused-parameter -Wwrite-strings"
+CC=`printf "all:\\n\\t@echo \\\$(CC)\\n" | env -i make -f -`
+CFLAGS="-g -W -Wall -Wmissing-prototypes -Wstrict-prototypes -Wwrite-strings"
+CFLAGS="${CFLAGS} -Wno-unused-parameter"
 LDADD=
 LDFLAGS=
 LD_OHASH=