Keep vanetza-idf in obu-firmware, so a plain clone builds the firmware

obu-firmware builds against the vanetza-idf C-ITS library, which until now
came from the colleague's microbu-esp32c5 tree beside the repository and was
not tracked here, so a clone of this repository could not build the firmware
it ships. The library alone is now part of obu-firmware, as
obu-firmware/external/vanetza-idf: their external/vanetza-idf at commit
cf4b99f, unchanged (9775 files; see its PROVENANCE.md). CMake takes it from
there by default; -DVANETZA_IDF_DIR still points the build elsewhere.

The rest of the colleague's tree (their own VAM firmware, PKI tooling,
station-link Python tools, the V2X2MAP bridge) stays out of this repository
and gitignored; nothing is pushed to their repository. NOTES.md, docs/06,
TODO.md and the pcap verifier's usage line point at the new location.

obu-firmware/external/vanetza-idf/vanetza/asn1/support/RELATIVE-OID_xer.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>.
+ * All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include "asn_internal.h"
+#include "RELATIVE-OID.h"
+
+static enum xer_pbd_rval
+RELATIVE_OID__xer_body_decode(const asn_TYPE_descriptor_t *td, void *sptr,
+                              const void *chunk_buf, size_t chunk_size) {
+    RELATIVE_OID_t *st = (RELATIVE_OID_t *)sptr;
+    const char *chunk_end __attribute__((unused)) = (const char *)chunk_buf + chunk_size;
+    const char *endptr;
+    asn_oid_arc_t s_arcs[6];
+    asn_oid_arc_t *arcs = s_arcs;
+    ssize_t num_arcs;
+    int ret;
+
+    (void)td;
+
+    num_arcs = OBJECT_IDENTIFIER_parse_arcs(
+        (const char *)chunk_buf, chunk_size, arcs,
+        sizeof(s_arcs) / sizeof(s_arcs[0]), &endptr);
+    if(num_arcs < 0) {
+        /* Expecting at least one arc arcs */
+        return XPBD_BROKEN_ENCODING;
+    } else if(num_arcs == 0) {
+        return XPBD_NOT_BODY_IGNORE;
+    }
+    assert(endptr == chunk_end);
+
+    if((size_t)num_arcs > sizeof(s_arcs) / sizeof(s_arcs[0])) {
+        arcs = (asn_oid_arc_t *)MALLOC(num_arcs * sizeof(arcs[0]));
+        if(!arcs) return XPBD_SYSTEM_FAILURE;
+        ret = OBJECT_IDENTIFIER_parse_arcs((const char *)chunk_buf, chunk_size,
+                                           arcs, num_arcs, &endptr);
+        if(ret != num_arcs) {
+            return XPBD_SYSTEM_FAILURE;  /* assert?.. */
+        }
+    }
+
+    /*
+     * Convert arcs into BER representation.
+     */
+    ret = RELATIVE_OID_set_arcs(st, arcs, num_arcs);
+    if(arcs != s_arcs) FREEMEM(arcs);
+
+    return ret ? XPBD_SYSTEM_FAILURE : XPBD_BODY_CONSUMED;
+}
+
+asn_dec_rval_t
+RELATIVE_OID_decode_xer(const asn_codec_ctx_t *opt_codec_ctx,
+                        const asn_TYPE_descriptor_t *td, void **sptr,
+                        const char *opt_mname, const void *buf_ptr,
+                        size_t size) {
+    return xer_decode_primitive(opt_codec_ctx, td,
+                                sptr, sizeof(RELATIVE_OID_t), opt_mname,
+                                buf_ptr, size, RELATIVE_OID__xer_body_decode);
+}
+
+asn_enc_rval_t
+RELATIVE_OID_encode_xer(const asn_TYPE_descriptor_t *td, const void *sptr,
+                        int ilevel, enum xer_encoder_flags_e flags,
+                        asn_app_consume_bytes_f *cb, void *app_key) {
+    const RELATIVE_OID_t *st = (const RELATIVE_OID_t *)sptr;
+    asn_enc_rval_t er = {0,0,0};
+
+    (void)ilevel;  /* Unused argument */
+    (void)flags;  /* Unused argument */
+
+    if(!st || !st->buf)
+        ASN__ENCODE_FAILED;
+
+    er.encoded = RELATIVE_OID__dump_body(st, cb, app_key);
+    if(er.encoded < 0) ASN__ENCODE_FAILED;
+
+    ASN__ENCODED_OK(er);
+}