If an ICD supports any of the following functions, they must be
queryable with vk_icdGetInstanceProcAddr:
vk_icdNegotiateLoaderICDInterfaceVersion
vk_icdGetPhysicalDeviceProcAddr
vk_icdEnumerateAdapterPhysicalDevices (Windows only)
In addition, these functions no longer need to be exported directly.
These changes allow drivers to no longer export the 'loader-icd interface'
functions which previously had to be exported. This change aids in future
extension work which aims to provide the ability to load drivers without
installing them to the system.
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.
