TT#14008 conditionally disable spandsp build test

When building using with_transcoding=no we should not expect spandsp to
be available as it's not even being used.

closes #1267

Change-Id: I2c8e0407b4dd46cfdd5322cd377b664955ad7c74

lib/spandsp_logging-test.c

@@ -1,3 +1,4 @@
+#ifdef WITH_TRANSCODING
 #include <inttypes.h>
 #include <sys/types.h>
 #include <stdbool.h>
@@ -18,3 +19,8 @@ int main(void) {
 	my_span_mh(NULL);
 	return 0;
 }
+#else
+int main(void) {
+	return 0;
+}
+#endif