https://bugs.gentoo.org/673390

--- a/sfbpf/Makefile.am
+++ b/sfbpf/Makefile.am
@@ -43,13 +43,14 @@
 libsfbpf_la_LDFLAGS = -version-info 0:1:0 @XCCFLAGS@
 
 # use of $@ and $< here is a GNU idiom that borks BSD
-sf_scanner.c: $(srcdir)/scanner.l
+sf_scanner.c: $(srcdir)/scanner.l tokdefs.h
 	@rm -f $(srcdir)/sf_scanner.c
 	$(srcdir)/runlex.sh $(V_LEX) -osf_scanner.c $(srcdir)/scanner.l
 
 sf_scanner.o: sf_scanner.c tokdefs.h
 
 tokdefs.h: sf_grammar.c
+
 sf_grammar.c: $(srcdir)/grammar.y
 	@rm -f sf_grammar.c tokdefs.h
 	$(V_YACC) -d $(srcdir)/grammar.y