diff --git a/putty.h b/putty.h
index 1477a71d..57c23442 100644
--- a/putty.h
+++ b/putty.h
@@ -2492,9 +2492,6 @@ extern const char commitid[];
 /*
  * Exports from unicode.c in platform subdirs.
  */
-#ifndef CP_UTF8
-#define CP_UTF8 65001
-#endif
 /* void init_ucs(void); -- this is now in platform-specific headers */
 bool is_dbcs_leadbyte(int codepage, char byte);
 int mb_to_wc(int codepage, int flags, const char *mbstr, int mblen,
diff --git a/windows/platform.h b/windows/platform.h
index 098b3bc3..aff153ae 100644
--- a/windows/platform.h
+++ b/windows/platform.h
@@ -194,6 +194,7 @@ void centre_window(HWND hwnd);
 
 #define DEFAULT_CODEPAGE CP_ACP
 #define USES_VTLINE_HACK
+#define CP_UTF8 65001
 
 #ifndef NO_GSSAPI
 /*