Possible solution:
On macOS, replace MoltenVK shared library with tiny stub, empty file ore something like that, because it is loaded at runtime with dlopen.
On iOS, put MoltenVK static library into GFXStream implementation, and add empty vkGetInstanceProcAddr in GFXStream stub, since vkGetInstanceProcAddr it is linked strongly to ensure MoltenVK static library is actually linked.
Possible solution:
On macOS, replace MoltenVK shared library with tiny stub, empty file ore something like that, because it is loaded at runtime with dlopen.
On iOS, put MoltenVK static library into GFXStream implementation, and add empty vkGetInstanceProcAddr in GFXStream stub, since vkGetInstanceProcAddr it is linked strongly to ensure MoltenVK static library is actually linked.