--- a/src/Mixfix/Makefile.am
+++ b/src/Mixfix/Makefile.am
@@ -82,7 +82,7 @@
 EXTRA_libmixfix_a_SOURCES = \
 	compiler.cc
 
-BUILT_SOURCES = surface.yy surface.cc surface.h lexer.cc tokenizer.cc
+BUILT_SOURCES = surface.cc lexer.cc tokenizer.cc
 CLEANFILES = surface.yy surface.cc surface.h lexer.cc tokenizer.cc
 
 surface.yy: \
@@ -97,7 +97,9 @@
 	$(srcdir)/bottom.yy \
 	> surface.yy
 
-surface.cc surface.h: surface.yy
+surface.h: surface.yy
+
+surface.cc: surface.h
 	$(BISON) -dv surface.yy -o surface.c
 	mv surface.c surface.cc