Add native file dialog library.

https://github.com/mlabbe/nativefiledialog.git
5cfe5002eb0fac1e49777a17dec70134147931e2

nfd/nfd_common.h

@@ -0,0 +1,37 @@
+/*
+  Native File Dialog
+
+  Internal, common across platforms
+
+  http://www.frogtoss.com/labs
+ */
+
+
+#ifndef _NFD_COMMON_H
+#define _NFD_COMMON_H
+
+#include "nfd.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define NFD_MAX_STRLEN 256
+#define _NFD_UNUSED(x) ((void)x)
+
+#define NFD_UTF8_BOM "\xEF\xBB\xBF"
+
+
+void  *NFDi_Malloc( size_t bytes );
+void   NFDi_Free( void *ptr );
+void   NFDi_SetError( const char *msg );
+int    NFDi_SafeStrncpy( char *dst, const char *src, size_t maxCopy );
+size_t NFDi_UTF8_Strlen( const nfdchar_t *str );
+int    NFDi_IsFilterSegmentChar( char ch );
+    
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif