diff --git a/tests/Makefile.am b/tests/Makefile.am
index 91ca5690d..039690d34 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -322,10 +322,14 @@ TESTOPTS = -L
 
 FLEX = $(top_builddir)/src/flex
 
-.l.c: $(FLEX)
+.l.c: 
+
+%.c: %.l $(FLEX)
 	$(AM_V_LEX)$(FLEX) $(TESTOPTS) -o $@ $<
 
-.ll.cc: $(FLEX)
+.ll.cc:
+
+%.cc: %.ll $(FLEX)
 	$(AM_V_LEX)$(FLEX) $(TESTOPTS) -+ -o $@ $<
 
 #want line numbers, so override the default rule
@@ -359,7 +363,9 @@ bison_yylval_scanner.h: bison_yylval_scanner.c
 # automake does not support compiling flex scanners output in C as C++
 # so we explicitly sayhow, using the .lll suffix for the lex input file
 
-.lll.cc: $(FLEX)
+.lll.cc:
+
+%.cc: %.lll $(FLEX)
 	$(AM_V_LEX)$(FLEX) $(TESTOPTS) -o $@ $<
 
 header_nr_main.$(OBJEXT): header_nr_scanner.h
@@ -400,11 +406,15 @@ top.h: top.c
 # Build rules for non-C back ends
 
 .l.go:
+
+%.go: %.l $(FLEX)
 	$(AM_V_LEX)$(FLEX) $(TESTOPTS) -o $@ $<
 
 # This is a temporary fake rule for use while the Go back end still
 # actually generates C.
 .go:
+
+%.o: %.go
 	$(CC) $< -o $*_go
 
 # Most test productions can be autogenerated from ruleset files, but