The loader has never searched for `GetInstanceProcAddr` or `GetDeviceProcAddr`,
yet has documented that Layer Interface Version 1 supports layers that export
those functions.
### Layer Interface Version 1
A layer supporting interface version 1 had the following behavior:
- 1. `GetInstanceProcAddr` and `GetDeviceProcAddr` were directly exported
+ 1. `vkGetInstanceProcAddr` and `vkGetDeviceProcAddr` were directly exported
2. The layer manifest file was able to override the names of the
`GetInstanceProcAddr` and `GetDeviceProcAddr`functions.