download asn1c from oai gitlab

the official asn1c repository at github posed problems to
some people in the past. It's better to have it locally
for such a critical piece of the software.

openair3/S1AP/MESSAGES/ASN1/asn1cpatch_2.p0

@@ -1,22 +0,0 @@
---- skeletons/OCTET_STRING.c.orig	2015-04-28 10:40:04.036970492 +0200
-+++ skeletons/OCTET_STRING.c	2015-04-28 10:40:09.619970869 +0200
-@@ -159,7 +159,7 @@
- }
- 
- static struct _stack *
--_new_stack() {
-+_new_stack(void) {
- 	return (struct _stack *)CALLOC(1, sizeof(struct _stack));
- }
- 
---- skeletons/converter-sample.c.orig	2015-04-28 10:40:32.164972391 +0200
-+++ skeletons/converter-sample.c	2015-04-28 10:40:37.140972727 +0200
-@@ -353,7 +353,7 @@
- } DynamicBuffer;
- 
- static void
--buffer_dump() {
-+buffer_dump(void) {
- 	uint8_t *p = DynamicBuffer.data + DynamicBuffer.offset;
- 	uint8_t *e = p + DynamicBuffer.length - (DynamicBuffer.unbits ? 1 : 0);
- 	if(!opt_debug) return;