Instead of allocating a temporary copy of the string, return a view of
it instead. Should improve the performance of system calls that take
file paths. Since it was allocating a string for every single syscall
that uses them in this case.
Removes the @PREFIX_ARCH@ replacement string in the thunks path.
The library prefix paths now get generated upfront and everything gets
replaced to handle the differences between multiarch distros.
Fixes Thunks on Arch and Fedora.
Fixes a spurious `No such file or directory` error when `ls` is trying
to query a path's xattributes that come from the emulated rootfs.
These syscalls don't support the *at variants, so it can't use the optimized `GetEmulatedFDPath` implementation.
It must also return an error on a found file path, which makes their
implementation be slightly different than the other user of of
`GetEmulatedPath`. In the case of error, it must only return an error
from the emulated path if it is /not/ ENOENT.
Before:
```
$ FEXInterpreter /usr/bin/ls -alth /usr/bin/wine-stable
/usr/bin/ls: /usr/bin/wine-stable: No such file or directory
-rwxr-xr-x 1 ryanh ryanh 1.1K Sep 24 2022 /usr/bin/wine-stable
```
After:
```
$ FEXInterpreter /usr/bin/ls -alth /usr/bin/wine-stable
-rwxr-xr-x 1 ryanh ryanh 1.1K Sep 24 2022 /usr/bin/wine-stable
```
Ryan Houdek