diff --git a/mongoose.h b/mongoose.h
index 9b8b98b89022c28ac8848d4dff25d00bc4dbd68c..d58667ff28f2ccab8f2d9b6ddc1ec3aff2716ae5 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -116,11 +116,13 @@
 
 /* Common stuff */
 
+#if !defined(WEAK)
 #if (defined(__GNUC__) || defined(__TI_COMPILER_VERSION__)) && !defined(_WIN32)
 #define WEAK __attribute__((weak))
 #else
 #define WEAK
 #endif
+#endif
 
 #ifdef __GNUC__
 #define NORETURN __attribute__((noreturn))