diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index 3877f78..4ea55e1 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -22,7 +22,7 @@
 			auth_milenage.c milenage/aes-encblock.c gea.c \
 			milenage/aes-internal.c milenage/aes-internal-enc.c \
 			milenage/milenage.c gan.c ipa.c gsm0341.c apn.c \
-			gsup.c gprs_gea.c gsm0503_conv.c
+			gsup.c gprs_gea.c gsm0503_conv.c oap.c
 libgsmint_la_LDFLAGS = -no-undefined
 libgsmint_la_LIBADD = $(top_builddir)/src/libosmocore.la