diff --git a/mongoose.c b/mongoose.c
index 90bfdf6b..901c32d1 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -20,8 +20,10 @@
 
 #if defined(_WIN32)
 #define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005
-#else
-#define _XOPEN_SOURCE      // For flockfile() on Linux
+#else 
+#ifdef __linux__
+#define _XOPEN_SOURCE 600     // For flockfile() on Linux
+#endif
 #define _LARGEFILE_SOURCE     // Enable 64-bit file offsets
 #define __STDC_FORMAT_MACROS  // <inttypes.h> wants this for C++
 #define __STDC_LIMIT_MACROS   // C++ wants that for INT64_MAX