embed steam Half-Life data into the image itself

allows also adding hlsdk libs to the image
makes it easier to build, manage, and run

container/build-and-test.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
-#set -eux
-set -ux
+set -eux
+
+echo DESTINATION_IS_WRITABLE > /opt/hl/testfile
 
 XDG_RUNTIME_DIR=/tmp weston \
 	--backend=headless \
@@ -11,14 +12,15 @@ XDG_RUNTIME_DIR=/tmp weston \
 
 build() {
 	pushd /build/xash3d-fwgs
-	./waf configure -T release -o /build/obj -8
-	./waf install --destdir=/build/out
+	./waf configure -T release -8 \
+		build \
+		install --destdir=/opt/hl
 	popd
 }
 
 rendertest() {
 	pushd /build/HLRTest/render
-	WAYLAND_DISPLAY=/tmp/wayland-headless ./rendertest.py --xash-dir /build/out run
+	WAYLAND_DISPLAY=/tmp/wayland-headless ./rendertest.py --xash-dir /opt/hl run
 	popd
 }