diff --git a/include/platform.hpp b/include/platform.hpp
index db3ce45b..ea0d65c2 100644
--- a/include/platform.hpp
+++ b/include/platform.hpp
@@ -57,7 +57,7 @@
 #endif
 
 // MingGW and Cygwin need POSIX functions which are not standard C explicitly enabled
-#if defined(__MINGW32__) || defined(__MINGW32__) || defined(__CYGWIN__)
+#if defined(__MINGW32__) || defined(__CYGWIN__)
 	#define _POSIX_C_SOURCE 200809L
 #endif