patch 8.0.0852: MS-Windows: possible crash when giving a message on startup

Problem:    MS-Windows: possible crash when giving a message on startup.
Solution:   Initialize length. (Yasuhiro Matsumoto, closes #1931)

Author: brammool

src/message.c

@@ -2639,13 +2639,14 @@ msg_puts_printf(char_u *str, int maxlen)
 # if defined(FEAT_MBYTE) && !defined(FEAT_GUI_MSWIN)
     if (enc_codepage >= 0 && (int)GetConsoleCP() != enc_codepage)
     {
-	int	len;
-	WCHAR	*widestr = (WCHAR *)enc_to_utf16(str, &len);
+	int	inlen = STRLEN(str);
+	int	outlen;
+	WCHAR	*widestr = (WCHAR *)enc_to_utf16(str, &inlen);
 
 	if (widestr != NULL)
 	{
-	    WideCharToMultiByte_alloc(GetConsoleCP(), 0, widestr, len,
-						    (LPSTR *)&ccp, &len, 0, 0);
+	    WideCharToMultiByte_alloc(GetConsoleCP(), 0, widestr, inlen,
+						 (LPSTR *)&ccp, &outlen, 0, 0);
 	    vim_free(widestr);
 	    s = str = ccp;
 	}

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    852,
 /**/
     851,
 /**/