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FLASHING.md says how to take a newer version of the colleague's tree (copy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/REAL.h

@@ -0,0 +1,126 @@
+/*-
+ * Copyright (c) 2004-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	ASN_TYPE_REAL_H
+#define	ASN_TYPE_REAL_H
+
+#include "asn_application.h"
+#include "asn_codecs_prim.h"
+
+#ifndef _ISOC99_SOURCE
+#define	_ISOC99_SOURCE		/* For ilogb() and quiet NAN */
+#endif
+#ifndef _BSD_SOURCE
+#define	_BSD_SOURCE		/* To reintroduce finite(3) */
+#endif
+#if	defined(__alpha)
+#include <sys/resource.h>	/* For INFINITY */
+#endif
+#include <math.h>
+
+#if	!(defined(NAN) || defined(INFINITY))
+static volatile double real_zero CC_NOTUSED = 0.0;
+#endif
+#ifndef	NAN
+#define	NAN	(0.0/0.0)
+#endif
+#ifndef	INFINITY
+#define	INFINITY	(1.0/0.0)
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum specialRealValue {
+    SRV__NOT_A_NUMBER,
+    SRV__MINUS_INFINITY,
+    SRV__PLUS_INFINITY
+} specialRealValue_e;
+extern struct specialRealValue_s {
+    char *string;
+    size_t length;
+    long dv;
+} specialRealValue[3];
+
+typedef ASN__PRIMITIVE_TYPE_t REAL_t;
+
+extern asn_TYPE_descriptor_t asn_DEF_REAL;
+extern asn_TYPE_operation_t asn_OP_REAL;
+
+#define REAL_free ASN__PRIMITIVE_TYPE_free
+
+#if !defined(ASN_DISABLE_PRINT_SUPPORT)
+asn_struct_print_f REAL_print;
+#endif  /* !defined(ASN_DISABLE_PRINT_SUPPORT) */
+
+asn_struct_compare_f REAL_compare;
+asn_struct_copy_f    REAL_copy;
+
+#define REAL_constraint asn_generic_no_constraint
+
+#if !defined(ASN_DISABLE_BER_SUPPORT)
+#define REAL_decode_ber ber_decode_primitive
+#define REAL_encode_der der_encode_primitive
+#endif  /* !defined(ASN_DISABLE_BER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_XER_SUPPORT)
+xer_type_decoder_f REAL_decode_xer;
+xer_type_encoder_f REAL_encode_xer;
+#endif  /* !defined(ASN_DISABLE_XER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+jer_type_decoder_f REAL_decode_jer;
+jer_type_encoder_f REAL_encode_jer;
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+oer_type_decoder_f REAL_decode_oer;
+oer_type_encoder_f REAL_encode_oer;
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_UPER_SUPPORT)
+per_type_decoder_f REAL_decode_uper;
+per_type_encoder_f REAL_encode_uper;
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) */
+#if !defined(ASN_DISABLE_APER_SUPPORT)
+per_type_decoder_f REAL_decode_aper;
+per_type_encoder_f REAL_encode_aper;
+#endif  /* !defined(ASN_DISABLE_APER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_RFILL_SUPPORT)
+asn_random_fill_f  REAL_random_fill;
+#endif  /* !defined(ASN_DISABLE_RFILL_SUPPORT) */
+
+/***********************************
+ * Some handy conversion routines. *
+ ***********************************/
+
+ssize_t REAL__dump(double d, int canonical, asn_app_consume_bytes_f *cb, void *app_key);
+
+/*
+ * Convert between native double type and REAL representation (DER).
+ * RETURN VALUES:
+ *  0: Value converted successfully
+ * -1: An error occurred while converting the value: invalid format.
+ */
+int asn_REAL2double(const REAL_t *real_ptr, double *d);
+int asn_double2REAL(REAL_t *real_ptr, double d);
+
+/*
+ * Downcast double to float while checking that no overflow occurs.
+ * This allows stricter control of the input data.
+ * RETURN VALUES:
+ *  0: The conversion was successful (perhaps with a loss of precision)
+ * -1: The conversion created overflow into infinities.
+ * The (outcome) is ALWAYS set to a value you'd expect from the
+ * standard silent float to double conversion behavior.
+ */
+int asn_double2float(double d, float *outcome);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* ASN_TYPE_REAL_H */