Trying _WIN32 for win32 detection.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22953 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavutil/log.c

@@ -33,7 +33,7 @@ static
 #endif
 int av_log_level = AV_LOG_INFO;
 
-#if (!HAVE_ISATTY) || defined(WIN32)
+#if (!HAVE_ISATTY) || defined(_WIN32)
 #define isatty(s) 0
 #endif