Fix default root ca path on Linux.

src/auth_event.c

@@ -111,13 +111,13 @@ belle_tls_crypto_config_t *belle_tls_crypto_config_new(void){
 	belle_tls_crypto_config_t *obj=belle_sip_object_new(belle_tls_crypto_config_t);
 
 	/*default to "system" default root ca, wihtout warranty...*/
-#ifdef __ANDROID__
+#if defined(__ANDROID__)
        belle_tls_crypto_config_set_root_ca(obj,"/system/etc/security/cacerts");
-#elif __linux
+#elif defined(__linux)
 	belle_tls_crypto_config_set_root_ca(obj,"/etc/ssl/certs");
 #elif defined(__APPLE__)
 	belle_tls_crypto_config_set_root_ca(obj,"/opt/local/share/curl/curl-ca-bundle.crt");
-#elif __QNX__
+#elif defined(__QNX__)
 	belle_tls_crypto_config_set_root_ca(obj,"/var/certs/web_trusted@personal@certmgr");
 #endif
 	obj->ssl_config = NULL;