diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6085865..638b572 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,5 +52,5 @@ install(DIRECTORY ${INCLUDE_DIR}/ DESTINATION include)
 if(MSVC)
 	target_compile_options(${PROJECT_NAME} PRIVATE /W4 /permissive-)
 else()
-	target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra -pedantic -Werror -Wno-newline-eof)
+	target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra -pedantic -Werror -Wno-newline-eof -Wno-language-extension-token)
 endif()
diff --git a/src/dcfg.c b/src/dcfg.c
index a1ccec6..0c72223 100644
--- a/src/dcfg.c
+++ b/src/dcfg.c
@@ -26,15 +26,12 @@
 #ifdef DCFG_PTHREAD_SUPPORT
 #	include <pthread.h>
 #else
-#	ifdef __USE_POSIX199506
-#		undef __USE_POSIX199506
-#	endif
-#	ifdef __USE_UNIX98
-#		undef __USE_UNIX98
-#	endif
+#	if defined __USE_POSIX199506 || defined __USE_UNIX98
+#	else
 typedef struct {
 	int unused;
 } pthread_mutex_t;
+#	endif
 
 void pthread_mutex_init(pthread_mutex_t *, void *);
 void pthread_mutex_destroy(pthread_mutex_t *);
@@ -1073,7 +1070,8 @@ Value *ast_to_value(dcfg_Instance *instance, AST *root)
 
 dcfg_Value *dcfg_parse(dcfg_Instance *instance, dcfg_StringView const file_path)
 {
-	char path_buf[file_path.size + 1] = {};
+	char path_buf[file_path.size + 1];
+	memset(path_buf, 0, sizeof(path_buf));
 	memcpy(path_buf, file_path.data, file_path.size);
 
 	char *abs = instance->realpath(path_buf);