Add NULL check for lpnFit in GetTextExtentExPointW

[Dmitry Timoshkov]

Hello.

Why there was no crash here, but holding gdi lock instead?

Changelog:
    Dmitry Timoshkov <dmitry at codeweavers.com>
    Add NULL check for lpnFit in GetTextExtentExPointW.

--- cvs/hq/wine/objects/font.c	Fri Apr  6 20:08:01 2001
+++ wine/objects/font.c	Mon Apr 16 15:43:01 2001
@@ -1154,7 +1154,7 @@
         else break;
     }
     size->cx = extent;
-    *lpnFit = nFit;
+    if(lpnFit) *lpnFit = nFit;
     ret = TRUE;
 
     TRACE("(%08x %s %d) returning %d %ld x %ld\n",