Errors importing upstream nall into bsnes repository

[carmiker]

When attempting to import the upstream nall repository into bsnes, a large number of errors occur at compile time.

Although there is quite an onslaught of error text, it all boils down to just two errors repeating many times, all in target-bsnes/program/platform.cpp, target-bsnes/program/program.cpp, target-bsnes/program/game-pak.cpp. and target-bsnes/program/game-rom.cpp:

target-bsnes/program/platform.cpp: In member function 'virtual nall::shared_pointer<nall::vfs::file> Program::open(uint, nall::string, nall::vfs::file::mode, bool)':
target-bsnes/program/platform.cpp:15:35: error: 'open' is not a member of 'nall::vfs::file'
   15 |       result = vfs::memory::file::open(Resource::System::Boards, sizeof(Resource::System::Boards));

target-bsnes/program/game-pak.cpp: In member function 'nall::shared_pointer<nall::vfs::file> Program::openPakSuperFamicom(nall::string, nall::vfs::file::mode)':
target-bsnes/program/game-pak.cpp:2:15: error: 'nall::vfs::fs' has not been declared
    2 |   return vfs::fs::file::open({superFamicom.location, name}, mode);

The solution to this is not obvious to me. Perhaps someone with a deeper understanding of bsnes and nall can offer some insight and lead the way to the most correct solution.