topology: Quit and show error message on big-endian machines

This tool can only support little-endian machines atm.
Many codes directly refer to  __le32/__le64 variables of ABI objects,
so will be broken on big-endian machines.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

src/topology/parser.c

@@ -371,10 +371,25 @@ void snd_tplg_verbose(snd_tplg_t *tplg, int verbose)
 	tplg->verbose = verbose;
 }
 
+static bool is_little_endian(void)
+{
+#ifdef __BYTE_ORDER
+	#if __BYTE_ORDER == __LITTLE_ENDIAN
+		return true;
+	#endif
+#endif
+	return false;
+}
+
 snd_tplg_t *snd_tplg_new(void)
 {
 	snd_tplg_t *tplg;
 
+	if (!is_little_endian()) {
+		SNDERR("error: cannot support big-endian machines\n");
+		return NULL;
+	}
+
 	tplg = calloc(1, sizeof(snd_tplg_t));
 	if (!tplg)
 		return NULL;

src/topology/tplg_local.h

@@ -12,6 +12,8 @@
 
 #include <limits.h>
 #include <stdint.h>
+#include <stdbool.h>
+#include <endian.h>
 #include <linux/types.h>
 
 #include "local.h"