This one small change allows the update_glslang_sources.py script to operate correctly with Python 2 and Python 3.
Change the string literal type to "bytes" so that it matches the type returned by the subprocess calls. Otherwise, under Python 3, the search for "known-good" in the list of remotes always fails. This is OK for the first execution of update_glsang_sources, since the remote is not there on the first run. But on subsequent runs, the search still fails to match and the script stops when trying to create a remote that already exists.
- remove unused variable to pass pylint
- Use another approach to detect if known-good remote is already
present to avoid the need for "ignore following errors" message.
Also added known-good mechanism to fetch latest validated spirv-tools.
Also added -Od and -Os to disable optimizer and optimize for size.
Fetching spirv-tools is optional for both glsl and hlsl. Legalization
of hlsl is done by default if spirv-opt is present at cmake time.
Optimization for glsl is currently done through the option -Os.
Legalization testing is currently only done on four existing shaders.
A separate baseLegalResults directory holds those results. All previous
testing is done with the optimizer disabled.
