Per https://en.cppreference.com/w/cpp/preprocessor/replace#.23_and_.23.23_operators the `##` behavior is a nonstandard extension; this extension seems to be supported by all compilers we care about, but IntelliSense in visual studio doesn't correctly handle it, resulting in false errors in the IDE (but not when compiling).
Per https://en.cppreference.com/w/cpp/preprocessor/replace#Function-like_macros C++20 introduced a workaround, where `__VA_OPT__(, )` generates a comma if and only if `__VA_ARGS__` is non-empty.
This PR replaces all occurrences, with the exception of Externals, DSPSpy (which is not likely to be edited in MSVC and does not target C++20 currently), and JitArm64_Integer.cpp (which uses `Function(__VA_ARGS__)`, and thus does not ever need a comma).
We use Dolphin code (specifically Common's ASSERT) from ImGui, and that will use C++20 features in the next commit, so ImGui needs to be built with C++20 for that to work properly.
Fixes https://bugs.dolphin-emu.org/issues/13017. With uCode switching, the existing instance of AXUCode is re-activated when GBAUCode is done, but if the state remains as WaitingForNextTask, it won't be able to do anything. Instead, it needs to be in WaitingForCmdListSize.
(When the AX uCode is resumed, startpc is set to 0x0030, at least for 0x07f88145; this is the same location as MAIL_RESUME jumps to, so DSP_RESUME should be sent when the resuming happens; that's already handled by AXUCode::Update.)
In the past, directory initialization could fail for two reasons:
The user was rejecting the storage permission, or external storage
wasn't mounted. With the introduction of scoped storage, the first of
these two couldn't happen anymore; if the user rejects the storage
permission, we just use the app-specific directory instead of the
dolphin-emu directory.
By making it so Dolphin force quits if external storage isn't mounted,
we can get rid of our code for handling retrying directory initialization
after it fails. I think this slight hit to UX is worth it considering
that basically nobody has an Android device with detachable primary
external storage anymore. And the UX hit is very small; the user just has
to manually open the app again after remounting external storage. The
toast about external storage not being mounted will still be displayed.
The recent merge of the splash screen PR may have made it so that the
code for handling directory initialization failing doesn't work anymore.
To be completely honest, I'm not sure how to even test this in 2022.
