Vulkan::Registry behaves differently in `add_subdirectory` vs
`find_package` builds. Which can result in build failures.
Also Vulkan::Registry never made sense as a CMake target and
was very brittle in numerous ways.
Better to provide a `VULKAN_HEADERS_REGISTRY_DIRECTORY` to users
instead and remove Vulkan::Registry completely.
closes#351
Currently the include directory is arch-dependent.
However, the location where the *.cmake files are installed
is arch-independent. This difference causes an issue with
cross compile environments.
Now as part of install 2 files are created:
- VulkanHeadersConfig.cmake
- VulkanHeadersConfigVersion.cmake
This allows usage of find_package
closes#157
Generate VulkanHeadersConfig.cmake and version file and install them.
To get the version information the header file vulkan_core.h is parsed.
In client code one can use `find_package(VulkanHeaders)` and get the
targets `Vulkan::Headers` and `Vulkan::Registry`.
The following additional files are generated and installed by CMake:
- VulkanHeadersConfig.cmake: searched for by find_package(VulkanHeaders)
- VulkanHeadersConfigVersion.cmake: provides version numbers
- VulkanHeadersTargets.cmake: CMake target definitions used by config file
