diff --git a/glfw/memfd.h b/glfw/memfd.h
index bdaa29808..ef24c64cc 100644
--- a/glfw/memfd.h
+++ b/glfw/memfd.h
@@ -8,7 +8,6 @@
 
 #ifdef HAS_MEMFD_CREATE
 
-#define _GNU_SOURCE
 #include <unistd.h>
 #include <sys/syscall.h>
 static inline int memfd_create(const char *name, unsigned int flags) {
@@ -36,6 +35,10 @@ static inline int memfd_create(const char *name, unsigned int flags) {
 
 #else
 
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
 static inline int
 createTmpfileCloexec(char* tmpname)
 {