removing warning about _CRT_SECURE_NO_WARNINGS if it is already defined

	modified:   mongoose.c

mongoose.c

@@ -19,7 +19,9 @@
 // THE SOFTWARE.
 
 #if defined(_WIN32)
+#if !defined(_CRT_SECURE_NO_WARNINGS)
 #define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005
+#endif
 #else
 #ifdef __linux__
 #define _XOPEN_SOURCE 600     // For flockfile() on Linux