editors/mg: document and fix ncurses requirement

Approved by:	ncurses blanket

editors/mg/Makefile

@@ -3,12 +3,14 @@
 
 PORTNAME=	mg
 PORTVERSION=	20160421
+PORTREVISION=	1
 CATEGORIES=	editors
 MASTER_SITES=	http://homepage.boetes.org/software/mg/
 
 MAINTAINER=	darcsis@gmail.com
 COMMENT=	Small, fast Emacs-like editor
 
+USES=		ncurses
 PLIST_FILES=	bin/mg man/man1/mg.1.gz
 PORTDOCS=	README tutorial
 

editors/mg/files/patch-GNUmakefile

@@ -0,0 +1,22 @@
+--- GNUmakefile.orig	2016-01-18 15:01:49 UTC
++++ GNUmakefile
+@@ -17,16 +17,10 @@ PKG_CONFIG=	/usr/bin/pkg-config
+ INSTALL=	/usr/bin/install
+ STRIP=		/usr/bin/strip
+ 
+-UNAME:=		$(shell uname)
+-ifeq ($(UNAME),FreeBSD)
+-  BSD_CPPFLAGS:=
+-  BSD_LIBS:=	-lutil
+-else
+-  BSD_CPPFLAGS:=$(shell $(PKG_CONFIG) --cflags libbsd-overlay)
+-  BSD_LIBS:=	$(shell $(PKG_CONFIG) --libs libbsd-overlay)
+-endif
++BSD_CPPFLAGS:=
++BSD_LIBS:=	-lutil
+ 
+-CURSES_LIBS=	-lcurses
++CURSES_LIBS=	-lncurses
+ 
+ CC?=		gcc
+ CFLAGS?=	-O2 -pipe

editors/mg/files/patch-Makefile

@@ -0,0 +1,11 @@
+--- Makefile.orig	2016-01-07 18:55:54 UTC
++++ Makefile
+@@ -2,7 +2,7 @@
+ 
+ PROG=	mg
+ 
+-LDADD+=	-lcurses -lutil
++LDADD+=	-lncurses -lutil
+ DPADD+=	${LIBCURSES} ${LIBUTIL}
+ 
+ # (Common) compile-time options: