This helps Visual Studio users have less clutter in their solution
explorer. This also updates spirv-tools to a newer version that folders
itself. This also updates spirv-headers so that spirv-tools compiles.
Visual Studio 2017 is able to build CMake-based projects directly be
opening the folder containing the CMakeLists.txt. However when doing
this shaderc is not able to find the Python executable (it uses
find_program instead of the special Python CMake module). Help shaderc
by setting the PYTHON_EXE variable before including its CMakeLists.txt
For shared library to work on Windows to work, we need to add
declspec(export) and declspec(import) annotations to the symbols to
export. This fixes the problem by making all libraries static on
Windows, but we'll need to revisit and do proper symbol exports.
Corentin Wallez
Austin Eng