Interpret %% correctly in printf format string.

diff --git a/dlls/msvcrt/wcs.c b/dlls/msvcrt/wcs.c
index 89e572d..0d4fa64 100644
--- a/dlls/msvcrt/wcs.c
+++ b/dlls/msvcrt/wcs.c
@@ -430,7 +430,7 @@
         /* output a single % character */
         if( *p == '%' )
         {
-            r = pf_output_stringW(out, p, 1);
+            r = pf_output_stringW(out, p++, 1);
             if( r<0 )
                 return r;
             continue;