add "--without-ns" to x11 configs for OSX

on OSX the configure script will select the "nextstep" window system
unless you explicitly tell it not to:

    % bmake configure |& egrep 'PKG_OPTIONS.emacs|What window system should Emacs use'
            PKG_OPTIONS.emacs = x11
      What window system should Emacs use?                    nextstep
    %

leaving pkgsrc in a bad state where it thinks it built an x11 version,
but instead emacs built a nextstep version.

add "--without-ns" to the x11 config option for OSX.  this
should not impact other platforms.

editors/emacs25/options.mk

@@ -1,4 +1,4 @@
-# $NetBSD: options.mk,v 1.3 2017/04/27 13:27:57 ryoon Exp $
+# $NetBSD: options.mk,v 1.4 2018/03/30 18:28:32 chuck Exp $
 
 PKG_OPTIONS_VAR=			PKG_OPTIONS.emacs
 PKG_SUPPORTED_OPTIONS=			dbus xft2 svg xml gnutls
@@ -75,6 +75,7 @@ PKG_OPTIONS+=		gtk3
 .if !empty(PKG_OPTIONS:Mx11)
 
 CONFIGURE_ARGS+=	--with-x
+CONFIGURE_ARGS+=	--without-ns
 CONFIGURE_ARGS+=	--with-xpm
 CONFIGURE_ARGS+=	--with-jpeg
 CONFIGURE_ARGS+=	--with-tiff