Keep the colleague's microbu-esp32c5 tree in this repository

obu-firmware builds against vanetza-idf from microbu-esp32c5/external, but
that tree was gitignored, so a clone of this repository could not build the
firmware it ships. It is now committed here as ordinary files in its own
folder, microbu-esp32c5/: the colleague's commit cf4b99f plus the V2X2MAP
bridge's signature verification (--trust) used on the bench. Nothing is
fetched from or pushed to the colleague's repository; this repository and
its remotes carry everything. The folder's own .gitignore keeps build output,
downloaded components and private key material out, as it did there; the
committed file set is identical to that repository's tracked files.

The ESP32-C5 is still flashed from obu-firmware/, which only takes
vanetza-idf from microbu-esp32c5/, so the two stay separate folders.
FLASHING.md says how to take a newer version of the colleague's tree (copy
it over the folder, rebuild, test, commit).

microbu-esp32c5/external/vanetza-idf/vanetza/asn1/support/ISO646String.c

@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include "asn_internal.h"
+#include "ISO646String.h"
+
+/*
+ * ISO646String basic type description.
+ */
+static const ber_tlv_tag_t asn_DEF_ISO646String_tags[] = {
+    (ASN_TAG_CLASS_UNIVERSAL | (26 << 2)),  /* [UNIVERSAL 26] IMPLICIT ...*/
+    (ASN_TAG_CLASS_UNIVERSAL | (4 << 2))    /* ... OCTET STRING */
+};
+#if !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT)
+static asn_per_constraints_t asn_DEF_ISO646String_per_constraints = {
+    { APC_CONSTRAINED, 7, 7, 0x20, 0x7e },   /* Value */
+    { APC_SEMI_CONSTRAINED, -1, -1, 0, 0 },  /* Size */
+    0, 0
+};
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT) */
+asn_TYPE_operation_t asn_OP_ISO646String = {
+    OCTET_STRING_free,
+#if !defined(ASN_DISABLE_PRINT_SUPPORT)
+    OCTET_STRING_print_utf8,  /* ASCII subset */
+#else
+    0,
+#endif  /* !defined(ASN_DISABLE_PRINT_SUPPORT) */
+    OCTET_STRING_compare,
+    OCTET_STRING_copy,
+#if !defined(ASN_DISABLE_BER_SUPPORT)
+    OCTET_STRING_decode_ber,  /* Implemented in terms of OCTET STRING */
+    OCTET_STRING_encode_der,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_BER_SUPPORT) */
+#if !defined(ASN_DISABLE_XER_SUPPORT)
+    OCTET_STRING_decode_xer_utf8,
+    OCTET_STRING_encode_xer_utf8,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_XER_SUPPORT) */
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+    OCTET_STRING_decode_jer_utf8,
+    OCTET_STRING_encode_jer_utf8,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+    OCTET_STRING_decode_oer,
+    OCTET_STRING_encode_oer,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+#if !defined(ASN_DISABLE_UPER_SUPPORT)
+    OCTET_STRING_decode_uper,
+    OCTET_STRING_encode_uper,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) */
+#if !defined(ASN_DISABLE_APER_SUPPORT)
+    OCTET_STRING_decode_aper,
+    OCTET_STRING_encode_aper,
+#else
+    0,
+    0,
+#endif  /* !defined(ASN_DISABLE_APER_SUPPORT) */
+#if !defined(ASN_DISABLE_RFILL_SUPPORT)
+    OCTET_STRING_random_fill,
+#else
+    0,
+#endif  /* !defined(ASN_DISABLE_RFILL_SUPPORT) */
+    0  /* Use generic outmost tag fetcher */
+};
+asn_TYPE_descriptor_t asn_DEF_ISO646String = {
+    "ISO646String",
+    "ISO646String",
+    &asn_OP_ISO646String,
+    asn_DEF_ISO646String_tags,
+    sizeof(asn_DEF_ISO646String_tags)
+      / sizeof(asn_DEF_ISO646String_tags[0]) - 1,
+    asn_DEF_ISO646String_tags,
+    sizeof(asn_DEF_ISO646String_tags)
+      / sizeof(asn_DEF_ISO646String_tags[0]),
+    {
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+        0,
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+#if !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT)
+        &asn_DEF_ISO646String_per_constraints,
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT) */
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+        0,
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+        ISO646String_constraint
+    },
+    0, 0,  /* No members */
+    0  /* No specifics */
+};