__mingw_wcstof() dereferencing of NULL pointer fixed

mingw-w64-crt/misc/mingw_wcstof.c

diff --git a/mingw-w64-crt/misc/mingw_wcstof.c b/mingw-w64-crt/misc/mingw_wcstof.c
index a19862a..01f0da0 100644
--- a/mingw-w64-crt/misc/mingw_wcstof.c
+++ b/mingw-w64-crt/misc/mingw_wcstof.c
@@ -18,14 +18,13 @@
   r = __mingw_strtof (n, &ep);  
   if (ep != NULL)
   {
-    *ep = 0;
     l2 = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, n, -1, NULL, 0);
     if (l2 > 0)
       l2 -= 1; /* Remove zero terminator from length.  */
-    *_EndPtr = (wchar_t *) &_Str[l2];
+    if (_EndPtr) *_EndPtr = (wchar_t *) &_Str[l2];
   }
   else
-   *_EndPtr = NULL;
+   if (_EndPtr) *_EndPtr = NULL;
   return r;
 }