Adds the VULKAN_HEADERS_ENABLE_MODULE option to control whether to build the Vulkan-Hpp module.
This is necessary to allow CI to pass while waiting for the MSVC version 17.11, which fixes an
internal compiler bug, to be added to github actions runners.
VULKAN_HEADERS_INSTALL was added since it was believed there was
a valid use case for it.
After looking into the use case that provoked this change there is
no reason to keep VULKAN_HEADERS_INSTALL as an option.
Here is the use case we do NOT want to support:
https://github.com/KhronosGroup/Vulkan-Headers/pull/416#issuecomment-1622318949
Fundamentally this problem is caused add_subdirectory/find_package
not being able to work together flawlessly.
Which isn't the responsibility of Vulkan-Headers to fix.
It's the responsibility of projects that consume Vulkan-Headers
to account for either method.
As described by the CMake maintainers:
https://discourse.cmake.org/t/idiomatic-way-to-handle-packages-and-add-subdirectory/8400
- It hasn't been handling windows (so it's been half implemented)
- It's a suboptimal method for exporting symbols for vulkan layers
since `--version-script` and `.def` files exists. Both of these
methods also don't risk name mangling.
- `--version-script` also has perf benefits since you can silence
exports from code you didn't intend to export
