Remnant of an early implementation.

In file included from src/input_common/gcadapter/gc_adapter.cpp:8:
src/./input_common/gcadapter/gc_adapter.h:11:10: fatal error: 'libusb.h' file not found
 #include <libusb.h>
          ^~~~~~~~~~

audio: Improving audio timing for multicore/single core

gcadapter: unbreak build on FreeBSD

 configure_graphics: Prevent unnecessary string copies in UpdateDeviceComboBox()

input_common: Add more libusb error checks for GC Adapter

AM: fix GetDisplayVersion

memory: Race-condition in pagetables.

cpu_interrupt_handler: Remove #pragma once from .cpp file

Port citra-emu/citra#5364: ".github: add a new issue template"

vulkan: Use VK_EXT_extended_dynamic_state when available

Reference libusb doesn't support DragonFly and FreeBSD because those
ship a different libusb implementation (supports 0.1, 1.0, 2.0 API).

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(usbi_alloc_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(usbi_alloc_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_has_capability) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_has_capability) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_has_capability) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(usbi_connect_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(usbi_disconnect_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_get_device_list) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_get_device_list) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_unref_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_unref_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_write
>>> referenced by core.c
>>>               core.c.o:(usbi_signal_event) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_read
>>> referenced by core.c
>>>               core.c.o:(usbi_clear_event) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_wrap_sys_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_wrap_sys_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_wrap_sys_device) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_open) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_backend
>>> referenced by core.c
>>>               core.c.o:(libusb_open) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_read
>>> referenced by core.c
>>>               core.c.o:(libusb_close) in archive externals/libusb/libusb.a

ld: error: undefined symbol: usbi_write
>>> referenced by core.c
>>>               core.c.o:(libusb_close) in archive externals/libusb/libusb.a

ld: error: too many errors emitted, stopping now (use -error-limit=0 to see all errors)
c++: error: linker command failed with exit code 1 (use -v to see invocation)

In file included from src/input_common/gcadapter/gc_adapter.cpp:8:
src/./input_common/gcadapter/gc_adapter.h:77:10: error: no template named 'unordered_map' in namespace 'std'
    std::unordered_map<int, bool> buttons;
    ~~~~~^
src/./input_common/gcadapter/gc_adapter.h:78:10: error: no template named 'unordered_map' in namespace 'std'
    std::unordered_map<int, u16> axes;
    ~~~~~^

configuration: Fix hotkeys that open file dialog in windowed mode

also, in case of failed to get of the basic version, we will try get it from application update.

While we're in the same area, we can make use of qOverload to tidy up
some function pointer casts.

Unlikely to impact performance at all, but this is essentially a "free"
transformation, so why not?

shader_cache: Fix use-after-free and orphan invalidation cache entries

GC Adapter Implementation

externals: Track opus as submodule instead of using conan

gl_buffer_cache: Copy to buffers created as STREAM_READ before downloading

Implement GetKeyCodeMap & GetKeyCodeMap2

Revert "cmake: fix fmt linking"

cmake: fix fmt linking

am: Stub GetIndirectLayerConsumerHandle

acc: ListOpenContextStoredUsers partial stub

Add LR triggers as axes, half press to initiate a press, add GC axis id in config, clarify some code blocks for better readability