diff --git a/src/common/convert_UTF.cc b/src/common/convert_UTF.cc
index fe0e155..4a5df1e 100644
--- a/src/common/convert_UTF.cc
+++ b/src/common/convert_UTF.cc
@@ -78,13 +78,6 @@
 #define UNI_SUR_LOW_START   (UTF32)0xDC00
 #define UNI_SUR_LOW_END     (UTF32)0xDFFF
 
-#ifndef false
-#define false	   0
-#endif
-#ifndef true
-#define true	    1
-#endif
-
 /* --------------------------------------------------------------------- */
 
 ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,