Fixes warning when wchar_t is used

.../dirent.c:121:3: warning: 'memset' used with length equal to number of elements without multiplication by element size [-Wmemset-elt-size]

Signed-off-by: David Wohlferd <dw@LimeGreenSocks.com>
(cherry picked from commit 9c24d01586e3986800455cfb3b120ee0b88337da)
diff --git a/mingw-w64-crt/misc/dirent.c b/mingw-w64-crt/misc/dirent.c
index f1ee0a2..4897cf4 100644
--- a/mingw-w64-crt/misc/dirent.c
+++ b/mingw-w64-crt/misc/dirent.c
@@ -118,7 +118,7 @@
   nd->dd_dir.d_ino = 0;
   nd->dd_dir.d_reclen = 0;
   nd->dd_dir.d_namlen = 0;
-  memset (nd->dd_dir.d_name, 0, 260 /*FILENAME_MAX*/);
+  memset (nd->dd_dir.d_name, 0, 260 * sizeof(nd->dd_dir.d_name[0])  /*FILENAME_MAX*/);
 
   return nd;
 }