diff --git a/Makefile b/Makefile
index 084b7cdf1..3a1d5ad98 100644
--- a/Makefile
+++ b/Makefile
@@ -281,19 +281,7 @@ clean: wire-clean
 	find . -name '*gcno' -delete
 
 update-mocks/%: %
-	@set -e; BASE=/tmp/mocktmp.$$$$.`echo $* | tr / _`; trap "rm -f $$BASE.*" EXIT; \
-	START=`fgrep -n '/* AUTOGENERATED MOCKS START */' $< | cut -d: -f1`;\
-	END=`fgrep -n '/* AUTOGENERATED MOCKS END */' $< | cut -d: -f1`; \
-	if [ -n "$$START" ]; then \
-	  echo $<: ; \
-	  head -n $$START $< > $$BASE.new; \
-	  (cat $$BASE.new; tail -n +$$END $<) > $$BASE.test.c; \
-	  if ! $(CC) $(CFLAGS) $$BASE.test.c -o $$BASE.out $(HELPER_OBJS) $(CCAN_OBJS) $(LDLIBS) 2>$$BASE.err; then \
-	    test/scripts/mockup.sh < $$BASE.err >> $$BASE.new; \
-	    sed -n 's,.*Generated stub for \(.*\) .*,\t\1,p' < $$BASE.new; \
-          fi; \
-	  tail -n +$$END $< >> $$BASE.new; mv $$BASE.new $<; \
-	fi
+	@tools/update-mocks.sh "$*"
 
 unittest/%: %
 	$(VALGRIND) $(VALGRIND_TEST_ARGS) $*
diff --git a/test/scripts/mockup.sh b/tools/mockup.sh
similarity index 94%
rename from test/scripts/mockup.sh
rename to tools/mockup.sh
index 1c88f3042..1fd293ab4 100755
--- a/test/scripts/mockup.sh
+++ b/tools/mockup.sh
@@ -15,7 +15,7 @@ if [ $# -eq 0 ]; then
 fi
 
 for SYMBOL; do
-    WHERE=$(grep -nH "^[a-z0-9_ ]* [*]*$SYMBOL(" daemon/*.h)
+    WHERE=$(grep -nH "^[a-z0-9_ ]* [*]*$SYMBOL(" */*.h )
     if [ x"$WHERE" != x ]; then
 	STUB='\n{ fprintf(stderr, "'$SYMBOL' called!\\n"); abort(); }'
     else
diff --git a/tools/update-mocks.sh b/tools/update-mocks.sh
new file mode 100755
index 000000000..4802f9147
--- /dev/null
+++ b/tools/update-mocks.sh
@@ -0,0 +1,39 @@
+#! /bin/sh
+# Script to rewrite the autogenerated mocks in a unit test between
+# /* AUTOGENERATED MOCKS START */ and /* AUTOGENERATED MOCKS END */
+# based on link failures.
+
+set -e
+FILE="$1"
+
+BASE=/tmp/mocktmp.$$.`echo $@ | tr / _`
+trap "mv $BASE.old $FILE; rm -f $BASE.*" EXIT
+
+START=`fgrep -n '/* AUTOGENERATED MOCKS START */' $FILE | cut -d: -f1`
+END=`fgrep -n '/* AUTOGENERATED MOCKS END */' $FILE | cut -d: -f1`
+
+if [ -n "$START" ]; then
+    mv $FILE $BASE.old
+    echo $FILE:
+    head -n $START $BASE.old > $FILE
+    tail -n +$END $BASE.old >> $FILE
+    # Try to make binary.
+    if ! make `echo $FILE | sed 's/.c$//'` 2> $BASE.err >/dev/null; then
+	tools/mockup.sh < $BASE.err >> $BASE.stubs
+	# If there are no link errors, maybe compile fail for other reason?
+	if ! fgrep -q 'Generated stub for' $BASE.stubs; then
+	    cat $BASE.err
+	    exit 1
+	fi
+	sed -n 's,.*Generated stub for \(.*\) .*,\t\1,p' < $BASE.stubs
+	head -n $START $BASE.old > $FILE
+	cat $BASE.stubs >> $FILE
+	tail -n +$END $BASE.old >> $FILE
+    else
+	echo "...build succeeded without stubs"
+    fi
+fi
+
+# All good.
+rm -f $BASE.*
+trap "" EXIT