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/config/Makefile.cygming

@@ -0,0 +1,21 @@
+NAME = glew32
+GLEW_DEST = /usr
+BINDIR = /usr/bin
+LIBDIR = /usr/lib/mingw
+INCDIR = /usr/include/mingw/GL
+# use gcc for linking, with ld it does not work
+CC := gcc -mno-cygwin
+LD := gcc -mno-cygwin
+LN :=
+LDFLAGS.GL = -lopengl32 -lgdi32 -luser32 -lkernel32
+LDFLAGS.EXTRA = -L$(LIBDIR)
+CFLAGS.EXTRA  += -fno-builtin -fno-stack-protector
+LDFLAGS.EXTRA += -nostdlib
+WARN = -Wall -W
+POPT = -O2
+BIN.SUFFIX = .exe
+LIB.SONAME    = lib$(NAME).dll
+LIB.DEVLNK    = lib$(NAME).dll.a   # for mingw this is the dll import lib
+LIB.SHARED    = $(NAME).dll
+LIB.STATIC    = lib$(NAME).a       # the static lib will be broken
+LDFLAGS.SO    = -shared -Wl,-soname,$(LIB.SONAME) -Wl,--out-implib,lib/$(LIB.DEVLNK)