diff --git a/src/Makefile.am b/src/Makefile.am
index 7c6e0d1d8..25b0718fe 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -6,6 +6,10 @@ INCLUDES = 					\
 noinst_LTLIBRARIES = libharfbuzz-1.la
 
 MAINSOURCES =  \
+	harfbuzz.c
+
+# included from harfbuzz.c
+INCLUDEDSOURCES = \
 	ftglue.c \
 	harfbuzz-buffer.c \
 	harfbuzz-gdef.c \
@@ -13,8 +17,6 @@ MAINSOURCES =  \
 	harfbuzz-gsub.c \
 	harfbuzz-open.c
 
-EXTRA_SOURCES = harfbuzz.c
-
 PUBLICHEADERS = \
 	harfbuzz.h \
 	harfbuzz-buffer.h \
@@ -55,5 +57,4 @@ EXTRA_DIST = 		\
 	COPYING.FTL	\
 	COPYING.GPL	\
 	COPYING		\
-	$(EXTRA_SOURCES)
-
+	$(INCLUDED_SOURCES)