On Linux, due to the way we include SDL2 as a submodule, it makes it
difficult for us to specify which SDL_config.h we intended to include.
Before, CMake would default to the dummy one included with SDL and
ignore the generated one.
This tells CMake to use the generated one. In addition, we define
USING_GENERATED_CONFIG_H to throw an error in case the dummy config is
used by accident. Fixes Vulkan not working on Linux yuzu-cmd.
yuzu requires CMake 3.15 yet find_program was using REQUIRED, which is
only available on 3.18 and later. Instead, we check for
"<VAR>-NOTFOUND".
In addition, check for additional requirements before building libusb or
FFmpeg with autotools. Otherwise, CMake configuration will pass yet
compilation will fail.
Fixes an issue where libusb.h wouldn't be found when building yuzu on
MSVC.
This only affects the "traditional" CMake pathway for linking libusb to
yuzu AKA MSVC. For autotools we still want to set these variables before
configuring SDL.
Delegates libusb external communication to externals/CMakeLists.txt
Ensures an interface library `usb` for every pathway
input_common just links to the `usb` library now
externals/libusb/CMakeLists.txt sets variables to override SDL2's libusb
finding
Other minor cleanup
Building libusb was also broken on GCC (and maybe Clang) on our
CMakeLists after upgrading to 1.0.24, but it was not being checked
because our 18.04 container had libusb installed on it.
This builds on the MinGW work from earlier and extends it to the rest of
the GNU toolchains. In addition we make use of pkg-config when present
to find libusb. pkg-config is preferrable because we can specify a
minimum required version.
Whatever those settings do breaks controller detection on Windows, at
least with the MinGW container. If-guard it against WIN32 and just let
SDL2 configure using its defaults, aside from static linking.
After updating to 1.0.24, MinGW fails to build libusb as a result of
numerous errors. So we build libusb their way and let them update the
nontrivial stuff.
This only applies to MinGW: the old path is still in use for Linux
toolchains as well as MSVC.
This will dynamically link libusb, since I hit build errors with the old
way we used to resolve the conflict with SDL2.
6b6b9e593d does not exist on FFmpeg master, and tag n4.3.1 requires
manually fetching all of FFmpeg's tags. `git` reports that the commit
does not exist initially and can be confusing as a result. Instead,
checkout the immediately previous commit from n4.3.1 on their master
branch.
