Ports: Add flex and pcre2 ports

Ports/pcre2/package.sh

@@ -0,0 +1,5 @@
+#!/bin/bash ../.port_include.sh
+port=pcre2
+version=10.34
+useconfigure=true
+files="https://ftp.pcre.org/pub/pcre/pcre2-10.34.tar.gz pcre2-10.34.tar.gz"

Ports/pcre2/patches/fix-autoconf.patch

@@ -0,0 +1,10 @@
+--- pcre2-10.34/config.sub.orig	Sun Jan 19 18:21:01 2020
++++ pcre2-10.34/config.sub	Sun Jan 19 18:21:19 2020
+@@ -1364,6 +1364,7 @@
+ 	# Each alternative MUST end in a * to match a version number.
+ 	# -sysv* is not here because it comes later, after sysvr4.
+ 	-gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
++	      | -serenity* \
+ 	      | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
+ 	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
+ 	      | -sym* | -kopensolaris* | -plan9* \

Ports/pcre2/patches/fix-pcre2test.patch

@@ -0,0 +1,11 @@
+--- pcre2-10.34/src/pcre2test.c.orig	Sun Jan 19 18:24:43 2020
++++ pcre2-10.34/src/pcre2test.c	Sun Jan 19 18:24:59 2020
+@@ -8604,7 +8604,7 @@
+   else if (strcmp(arg, "-S") == 0 && argc > 2 &&
+       ((uli = strtoul(argv[op+1], &endptr, 10)), *endptr == 0))
+     {
+-#if defined(_WIN32) || defined(WIN32) || defined(__minix) || defined(NATIVE_ZOS) || defined(__VMS)
++#if defined(_WIN32) || defined(WIN32) || defined(__minix) || defined(NATIVE_ZOS) || defined(__VMS) || defined(__serenity__)
+     fprintf(stderr, "pcre2test: -S is not supported on this OS\n");
+     exit(1);
+ #else