includes: add forward declartion of external types

Change-Id: Ifbf0a045a6391694155f6627967f2d92b930d765
---
M include/osmocom/sgsn/gprs_bssgp.h
1 file changed, 3 insertions(+), 0 deletions(-)

diff --git a/include/osmocom/sgsn/gprs_bssgp.h b/include/osmocom/sgsn/gprs_bssgp.h
index 0feaa97..abfe9f1 100644
--- a/include/osmocom/sgsn/gprs_bssgp.h
+++ b/include/osmocom/sgsn/gprs_bssgp.h
@@ -2,6 +2,9 @@
 
 #include <osmocom/core/msgb.h>
 
+struct osmo_prim_hdr;
+struct sgsn_mm_ctx;
+
 /* Called by bssgp layer when a prim is received from lower layers. */
 int sgsn_bssgp_rx_prim(struct osmo_prim_hdr *oph);
 

