Update to 2.3.1.

Release announcement: https://www.lyx.org/announce/2_3_1.txt

print/lyx/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	lyx
 PORTVERSION=	${MAJOR_VERSION}.${MINOR_VERSION}
-PORTREVISION=	1
+DISTVERSIONSUFFIX=	-2
 CATEGORIES=	print editors
 MASTER_SITES=	ftp://ftp.lyx.org/pub/lyx/stable/${MAJOR_VERSION}.x/ \
 		http://www-ftp.lip6.fr/ftp/pub/lyx/stable/${MAJOR_VERSION}.x/ \
@@ -19,8 +19,10 @@ LICENSE_FILE=	${WRKSRC}/COPYING
 LIB_DEPENDS=	libboost_regex.so:devel/boost-libs \
 		libmythes-1.2.so:textproc/mythes
 
+WRKSRC=		${WRKDIR}/${DISTNAME:S,${DISTVERSIONSUFFIX}$$,,}
+
 MAJOR_VERSION=	2.3
-MINOR_VERSION=	0
+MINOR_VERSION=	1
 
 USES=		desktop-file-utils gmake iconv pkgconfig perl5 \
 		python:2.7 qt:5 shebangfix tar:xz

print/lyx/distinfo

@@ -1,3 +1,3 @@
-TIMESTAMP = 1526500182
-SHA256 (lyx-2.3.0.tar.xz) = 310f556adbfafd243f2c17a0be0d22fa50b9b4f7de41e66625cace8ea088b92b
-SIZE (lyx-2.3.0.tar.xz) = 15676680
+TIMESTAMP = 1544182147
+SHA256 (lyx-2.3.1-2.tar.xz) = f5c9450ba196ed9d49fbc573f65b10d1726d16a62453466957aba2a9f6d66f84
+SIZE (lyx-2.3.1-2.tar.xz) = 15800168

print/lyx/files/patch-gentoo_git-lyx-2.3.0-qt-5.11.patch

@@ -1,19 +0,0 @@
-https://gitweb.gentoo.org/repo/gentoo.git/plain/app-office/lyx/files/lyx-2.3.0-qt-5.11.patch
-
---- src/frontends/qt4/GuiDocument.cpp	2018-02-25 01:11:18.000000000 +0100
-+++ src/frontends/qt4/GuiDocument.cpp	2018-03-30 19:45:47.283928297 +0200
-@@ -68,11 +68,12 @@
- #include "frontends/alert.h"
- 
- #include <QAbstractItemModel>
--#include <QHeaderView>
-+#include <QButtonGroup>
- #include <QColor>
- #include <QColorDialog>
- #include <QCloseEvent>
- #include <QFontDatabase>
-+#include <QHeaderView>
- #include <QScrollBar>
- #include <QTextBoundaryFinder>
- #include <QTextCursor>
-