ICU-20302 Fix wintz header file. (Thanks to Jungshik).

diff --git a/icu4c/source/common/wintz.h b/icu4c/source/common/wintz.h
index f98b1779b5d4b4eff78683c98577b34907514632..cd8565eef1ed3cb60ce57ed9720c096b2acf3fce 100644 (file)
--- a/icu4c/source/common/wintz.h
+++ b/icu4c/source/common/wintz.h
@@ -28,7 +28,7 @@ U_CDECL_BEGIN
 typedef struct _TIME_ZONE_INFORMATION TIME_ZONE_INFORMATION;
 U_CDECL_END
 
-U_CFUNC const char* U_EXPORT2
+U_INTERNAL const char* U_EXPORT2
 uprv_detectWindowsTimeZone();
 
 #endif /* U_PLATFORM_USES_ONLY_WIN32_API  */