Uses mailbox, then immediate for unlocked framerate depending on
support for either. Also adds support for FIFO_RELAXED.
This function now assumes vsync_mode was originially configured to a value
that the driver supports.
vk_swapchain: ChooseSwapPresentMode determines updates
Simplifies swapchain a bit and allows us to change the present mode
during guest runtime.
vk_swapchain: Fix MSVC error
vk_swapchain: Enforce available present modes
Some frontends don't check the value of vsync_mode before comitting it.
Just as well, since a driver update or misconfiguration could problems
in the swap chain.
vk_swapchain: Silence warnings
Silences GCC warnings implicit-fallthrough and shadow, which apparently
are not enabled on clang.
952b271092