hash.c: unused functions on non-Windows

* hash.c (invalid_envname, check_envname): not used on platforms
  other than Windows.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46546 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

hash.c

@@ -2722,9 +2722,7 @@ getenvblocksize()
 {
     return (rb_w32_osver() >= 5) ? 32767 : 5120;
 }
-#endif
 
-#if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
 NORETURN(static void invalid_envname(const char *name));
 
 static void