port/merge Eurecom APER support from OPENAIRMME

Eurecom has developed APER support for asn1c as part of the OPENAIRMME
softare (a LTE MME).  This is too important to let it bit-rout out
of asn1c.  Let's forward-port and merge it.
diff --git a/skeletons/per_encoder.h b/skeletons/per_encoder.h
index 95a6506..e3b9190 100644
--- a/skeletons/per_encoder.h
+++ b/skeletons/per_encoder.h
@@ -38,6 +38,12 @@
 	size_t buffer_size	/* Initial buffer size (max) */
 );
 
+asn_enc_rval_t aper_encode_to_buffer(
+	struct asn_TYPE_descriptor_s *type_descriptor,
+	void *struct_ptr,	   /* Structure to be encoded */
+	void *buffer,		   /* Pre-allocated buffer */
+	size_t buffer_size	   /* Initial buffer size (max) */
+);
 /*
  * A variant of uper_encode_to_buffer() which allocates buffer itself.
  * Returns the number of bytes in the buffer or -1 in case of failure.
@@ -52,6 +58,11 @@
 	void **buffer_r		/* Buffer allocated and returned */
 );
 
+ssize_t
+aper_encode_to_new_buffer(struct asn_TYPE_descriptor_s *td,
+						  asn_per_constraints_t *constraints,
+						  void *sptr,
+						  void **buffer_r);
 /*
  * Type of the generic PER encoder function.
  */