patch 8.0.0460: can't build on HPUX

Problem:    Can't build on HPUX.
Solution:   Fix argument names in vim_stat(). (John Marriott)
diff --git a/src/misc2.c b/src/misc2.c
index 4777129..522fcb6 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -3365,7 +3365,7 @@
  * The Vim code assumes a trailing slash is only ignored for a directory.
  */
     static int
-illegal_slash(char *name)
+illegal_slash(const char *name)
 {
     if (name[0] == NUL)
 	return FALSE;	    /* no file name is not illegal */
@@ -3384,7 +3384,7 @@
 {
     /* On Solaris stat() accepts "file/" as if it was "file".  Return -1 if
      * the name ends in "/" and it's not a directory. */
-    return illegal_slash(n) ? -1 : stat(n, p);
+    return illegal_slash(name) ? -1 : stat(name, stp);
 }
 #endif