gdiplus: Allow null-terminated strings in GdipDrawString.
diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 968c89f..f63e073 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -1296,6 +1296,8 @@
         return NotImplemented;
     }
 
+    if(length == -1) length = lstrlenW(string);
+
     stringdup = GdipAlloc(length * sizeof(WCHAR));
     if(!stringdup) return OutOfMemory;