diff --git a/lib/Makefile.am b/lib/Makefile.am
index 9dab986..5afed28 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -8,6 +8,7 @@ lib_LTLIBRARIES = libpam.la
 
 noinst_HEADERS = \
 	openpam_constants.h \
+	openpam_ctype.h \
 	openpam_debug.h \
 	openpam_impl.h \
 	openpam_strlcat.h \