diff --git a/Makefile.am b/Makefile.am
index 54d2116..e4430d8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -29,7 +29,7 @@ cinclude_HEADERS = pal.h palmac.h
 
 noinst_HEADERS = $(PRIVATE_INCLUDES)
 
-PRIVATE_INCLUDES = pal1.h
+PRIVATE_INCLUDES = pal1.h pal1sofa.h
 
 PUBLIC_C_FILES = \
 palAddet.c \