--- /dev/null
+#! /bin/sh
+
+# First, test normal config.
+if ! make -s; then
+ echo Normal config failed.
+ exit 1
+fi
+
+# Now, remove one HAVE_ at a time.
+cp config.h original-config.h
+trap "mv original-config.h config.h && rm -f .newconfig" EXIT
+
+while grep -q '1$' config.h; do
+ tr '\012' @ < config.h | sed 's/1@/0@/' | tr @ '\012' > .newconfig
+ diff -u config.h .newconfig
+ mv .newconfig config.h
+ if ! make -s; then
+ echo Failed config:
+ cat config.h
+ exit 1
+ fi
+done