diff --git a/modules/preprocs/yapp/Makefile.inc b/modules/preprocs/yapp/Makefile.inc
index dfdafb9e..e04a51c2 100644
--- a/modules/preprocs/yapp/Makefile.inc
+++ b/modules/preprocs/yapp/Makefile.inc
@@ -4,7 +4,7 @@ YASMPREPROCFILES += \
 	src/preprocs/yapp/yapp-preproc.h \
 	src/preprocs/yapp/yapp-preproc.c \
 	src/preprocs/yapp/yapp-token.h \
-	src/preprocs/yapp/yapp-token.l
+	$(top_srcdir)/src/preprocs/yapp/yapp-token.l
 
 BUILT_SOURCES += \
 	yapp-token.c
diff --git a/src/preprocs/yapp/Makefile.inc b/src/preprocs/yapp/Makefile.inc
index dfdafb9e..e04a51c2 100644
--- a/src/preprocs/yapp/Makefile.inc
+++ b/src/preprocs/yapp/Makefile.inc
@@ -4,7 +4,7 @@ YASMPREPROCFILES += \
 	src/preprocs/yapp/yapp-preproc.h \
 	src/preprocs/yapp/yapp-preproc.c \
 	src/preprocs/yapp/yapp-token.h \
-	src/preprocs/yapp/yapp-token.l
+	$(top_srcdir)/src/preprocs/yapp/yapp-token.l
 
 BUILT_SOURCES += \
 	yapp-token.c