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_initd.pl

@@ -0,0 +1,45 @@
+#!/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 lib '.';
+do 'bin/make.pl';
+
+## Output declarations for the _glewInit_[extension] functions defined
+## by make_init.pl script.  These are necessary for for initializers to
+## call each other, such as a core GL 3 context that depends on certain
+## extensions.
+
+#-------------------------------------------------------------------------------
+
+my @extlist = ();
+my %extensions = ();
+
+our $type = shift;
+
+if (@ARGV)
+{
+    @extlist = @ARGV;
+
+	foreach my $ext (sort @extlist)
+	{
+		my ($extname, $exturl, $extstring, $reuse, $types, $tokens, $functions, $exacts) = 
+			parse_ext($ext);
+
+		#print "#ifdef $extname\n\n";
+		if (keys %$functions)
+		{
+			print "static GLboolean _glewInit_$extname ();\n";
+		}
+		#print "#endif /* $extname */\n\n";
+	}
+}