A small, nonexhaustive set of warning fixes. The DiscIO Volume change
is a workaround for a GCC bug [1] that causes returning an unengaged
std::optional to emit annoying -Wmaybe-uninitialized warnings.
This last change alone fixes pages upon pages of warnings since
Volume.h is included from several files.
-Wstringop-truncation is another irrelevant warning for us, but
unfortunately there seems to be no way to disable it without
adding ugly pragmas wherever the warning appears.
string_view is a thin wrapper around C strings, so it's more efficient
for constant strings than C++ strings.
The unordered_set<> also adds extra runtime overhead. For small arrays,
a simple linear search works. For larger arrays, std::binary_search()
works better than linear but without the unordered_set<> overhead.
ShouldBeDualLayer(): Removed a duplicate "SK8X52" entry.
This happens if someone manually downloads a regular datfile from
redump.org and puts it where Dolphin stores datfiles. Dolphin needs
"special" datfiles that contain fields for serials and versions.
Before this change, all discs (except Datel discs) would show up as
"Unknown disc" when using a regular datfile.
This was making it impossible to use the Redump.org integration
without first manually creating a Redump folder in the Cache folder.
https://bugs.dolphin-emu.org/issues/11885