Make soxr, metadata and apple_alac defaults if support for them is included in the build configuration.

common.c

@@ -1282,6 +1282,9 @@ char *get_version_string() {
   char *version_string = malloc(1024);
   if (version_string) {
     strcpy(version_string, PACKAGE_VERSION);
+#ifdef CONFIG_LIBDAEMON
+    strcat(version_string, "-libdaemon");
+#endif
 #ifdef CONFIG_MBEDTLS
     strcat(version_string, "-mbedTLS");
 #endif
@@ -1300,6 +1303,9 @@ char *get_version_string() {
 #ifdef CONFIG_DNS_SD
     strcat(version_string, "-dns_sd");
 #endif
+#ifdef CONFIG_EXTERNAL_MDNS
+    strcat(version_string, "-external_mdns");
+#endif
 #ifdef CONFIG_ALSA
     strcat(version_string, "-ALSA");
 #endif