Introduce a default buffer getter that lazily constructs an empty
buffer. This is intended to match OpenGL's buffer 0.

Use this for disabled vertex and uniform buffers.

While we are at it, include vertex buffer usages for staging buffers to
silence validation errors.

On NVN buffers can be enabled but have no size. According to deko3d and
the behavior we see in Animal Crossing: New Horizons these buffers get
the special address of 0x1000 and limit themselves to 0xfff.

Implement buffers without a size by binding a null buffer to OpenGL
without a side.

https://github.com/devkitPro/deko3d/blob/1d1930beea093b5a663419e93b0649719a3ca5da/source/maxwell/gpu_3d_vbo.cpp#L62-L63

fixed_pipeline_state: Pack structure, use memcmp and CityHash on it

General: Resolve minor assorted warnings

core: arm_unicorn: Fix interpret fallback by temporarily mapping instruction page.

* audio_renderer: Preliminary BehaviorInfo

* clang format

* Fixed IsRevisionSupported

* fixed IsValidRevision

* Fixed logic error & spelling errors & crash

* Addressed issues

maxwell_3d: Initialize format attributes constant as one

Initialize quad_indexed_pass before uint8_pass

dynarmic: Add option to disable CPU JIT optimizations

Try to reduce log spam a bit by lowering log levels to Debug

vk_stream_buffer: Fix out of memory on boot on recent Nvidia drivers

service: Remove unused RequestParser instances

am: Resolve ineffective moves

Fixes Werror=reorder in gcc

dma_pusher: Remove reliance on the global system instance

vk_compute_pass: Implement indexed quads

With this, the video core is now has no calls to the global system
instance at all.

texture_cache/format_lookup_table: Fix incorrect green, blue, and alpha indices

hle_ipc: Remove std::size_t casts where applicable

yuzu/main: Add better popup texts and remove duplicated actions

track: Eliminate redundant copies

Unbreak Vulkan on FreeBSD

Unbreak -Werror=implicit-fallthrough with Clang

Render.Vulkan <Error> video_core/renderer_vulkan/renderer_vulkan.cpp:CreateInstance:131: Presentation not supported on this platform
Render.Vulkan <Error> video_core/renderer_vulkan/renderer_vulkan.cpp:CreateSurface:378: Presentation not supported on this platform
Core <Critical> core/core.cpp:Load:199: Failed to initialize system (Error 5)!

In file included from src/input_common/sdl/sdl_impl.cpp:16:
In file included from /usr/local/include/SDL2/SDL.h:32:
In file included from /usr/local/include/SDL2/SDL_main.h:25:
/usr/local/include/SDL2/SDL_stdinc.h:445:9: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case 3:         *_p++ = _val;   /* fallthrough */
        ^
/usr/local/include/SDL2/SDL_stdinc.h:445:9: note: insert '[[fallthrough]];' to silence this warning
        case 3:         *_p++ = _val;   /* fallthrough */
        ^
        [[fallthrough]];
/usr/local/include/SDL2/SDL_stdinc.h:445:9: note: insert 'break;' to avoid fall-through
        case 3:         *_p++ = _val;   /* fallthrough */
        ^
        break;
/usr/local/include/SDL2/SDL_stdinc.h:446:9: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case 2:         *_p++ = _val;   /* fallthrough */
        ^
/usr/local/include/SDL2/SDL_stdinc.h:446:9: note: insert '[[fallthrough]];' to silence this warning
        case 2:         *_p++ = _val;   /* fallthrough */
        ^
        [[fallthrough]];
/usr/local/include/SDL2/SDL_stdinc.h:446:9: note: insert 'break;' to avoid fall-through
        case 2:         *_p++ = _val;   /* fallthrough */
        ^
        break;
/usr/local/include/SDL2/SDL_stdinc.h:447:9: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
        case 1:         *_p++ = _val;   /* fallthrough */
        ^
/usr/local/include/SDL2/SDL_stdinc.h:447:9: note: insert '[[fallthrough]];' to silence this warning
        case 1:         *_p++ = _val;   /* fallthrough */
        ^
        [[fallthrough]];
/usr/local/include/SDL2/SDL_stdinc.h:447:9: note: insert 'break;' to avoid fall-through
        case 1:         *_p++ = _val;   /* fallthrough */
        ^
        break;
3 errors generated.

Pad FixedPipelineState's size to 384 bytes to be a multiple of 16.

Compare the whole struct with std::memcmp and hash with CityHash. Using
CityHash instead of a naive hash should reduce the number of collisions.
Improve used type traits to ensure this operation is safe.

With these changes the improvements to the hashable pipeline state are:

Optimized structure
Hash:            89 ns
Comparison:     103 ns
Construction*:  164 ns
Struct size:    384 bytes

Original structure
Hash:           148 ns
Equal:          174 ns
Construction*:  281 ns
Size:          1384 bytes

* Attribute state initialization is not measured

These measures are averages taken with std::chrono::high_accuracy_clock
on MSVC shipped on Visual Studio 16.6.0 Preview 2.1.

Reduce FixedPipelineState's size to 364 bytes.

Reduce FixedPipelineState's size to 600 bytes.

Reduce FixedPipelineState's size to 632 bytes.

Reduce FixedPipelineState's size from 1384 to 664 bytes

video_core: gl_shader_decompiler: Fix implicit fallthrough errors.

loader/nso: Resolve moves not occurring in DecompressSegment

service: hid: npad: Fix implicit fallthrough errors.

service/time: Minor changes