feat(gx): add incomplete 'CGxDeviceGLSDL' (#2)

* chore(build): add vendored SDL 3.0.0 library

* chore(build): add vendored glew-cmake-2.2.0 library

* feat(console): in the presence of -opengl launch flag, change GxApi to OpenGl

* feat(gx): add uncompleted CGxDeviceGLSDL targeting Windows and Linux

* chore(build): change SDL3 linkage from shared (bad) to to static (good)

vendor/glew-cmake-2.2.0/auto/bin/make_index.pl

@@ -0,0 +1,41 @@
+#!/usr/bin/env perl
+##
+## Copyright (C) 2008-2019, Nigel Stewart <nigels[]users sourceforge net>
+## Copyright (C) 2002-2008, Marcelo E. Magallon <mmagallo[]debian org>
+## Copyright (C) 2002-2008, Milan Ikits <milan ikits[]ieee org>
+##
+## This program is distributed under the terms and conditions of the GNU
+## General Public License Version 2 as published by the Free Software
+## Foundation or, at your option, any later version.
+
+use strict;
+use warnings;
+use File::Basename;
+
+use lib '.';
+do 'bin/make.pl';
+
+##
+## Make Index
+##
+## Output sorted array of extension strings for indexing into extension
+## enable/disable flags.  This provides a way to convert an extension string
+## into an integer index.
+##
+
+my @extlist = ();
+
+if (@ARGV)
+{
+	@extlist = @ARGV;
+
+	foreach my $ext (sort { basename($a) cmp basename($b) } @extlist)
+	{
+		my ($extname, $exturl, $extstring, $reuse, $types, $tokens, $functions, $exacts) = 
+			parse_ext($ext);
+
+		print "#ifdef $extname\n";
+		print "  \"$extname\",\n";
+		print "#endif\n";
+	}
+}