import gsup_client.c as new libosmo-gsup-client

This imports the code from osmo-msc 6afef893e17bce67e4d4119acd34d480ed03ba77
with minimal changes to make it compile.  Symbol renaming ot osmo_
prefix is done separately in a follow-up patch to have a as-clean-as-possible
import first.

Requires: libosmocore.git Change-Id Ie36729996abd30b84d1c30a09f62ebc6a9794950
Change-Id: Ief50054ad135551625b684ed8a0486f7af0b2940
diff --git a/.gitignore b/.gitignore
index d65cb68..571f5b1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,8 @@
 missing
 .deps
 
+*.pc
+
 src/db_test
 src/db_bootstrap.h
 src/osmo-hlr