diff --git a/include/osmocore/protocol/Makefile.am b/include/osmocore/protocol/Makefile.am
index 557950e..5df9fe7 100644
--- a/include/osmocore/protocol/Makefile.am
+++ b/include/osmocore/protocol/Makefile.am
@@ -1,3 +1,4 @@
-osmocore_proto_HEADERS = gsm_04_08.h gsm_04_11.h gsm_04_80.h gsm_08_58.h gsm_12_21.h gsm_08_08.h
+osmocore_proto_HEADERS = gsm_04_08.h gsm_04_11.h gsm_04_80.h gsm_08_58.h \
+			 gsm_12_21.h gsm_08_08.h gsm_04_12.h
 
 osmocore_protodir = $(includedir)/osmocore/protocol