diff --git a/src/Makefile.am b/src/Makefile.am
index 8d65294edb026ab2f9b7d2d53950a04b1c4baef5..dff2a1b8a0061ef29606a71b4146300e0e3ba1e4 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,7 +5,7 @@ INCLUDES = 					\
 
 noinst_LTLIBRARIES = libharfbuzz-1.la
 
-SOURCES =  \
+MAINSOURCES =  \
 	ftglue.c \
 	harfbuzz-buffer.c \
 	harfbuzz-dump.c \
@@ -34,7 +34,7 @@ PRIVATEHEADERS = \
 	harfbuzz-open-private.h
 
 libharfbuzz_1_la_SOURCES = \
-	$(SOURCES) \
+	$(MAINSOURCES) \
 	$(PUBLICHEADERS) \
 	$(PRIVATEHEADERS)