`network.cpp` has several error paths which either:
- report "Unhandled host socket error=n" and return `SUCCESS`, or
- switch on a few possible errors, log them, and translate them to
Errno; the same switch statement is copied and pasted in multiple
places in the code
Convert these paths to use a helper function `GetAndLogLastError`, which
is roughly the equivalent of one of the switch statements, but:
- handling more cases (both ones that were already in `Errno`, and a few
more I added), and
- using OS functions to convert the error to a string when logging, so
it'll describe the error even if it's not one of the ones in the
switch statement.
- To handle this, refactor the logic in `GetLastErrorMsg` to expose a
new function `NativeErrorToString` which takes the error number
explicitly as an argument. And improve the Windows version a bit.
Also, add a test which exercises two random error paths.
Allows our CI to catch more potential bugs. This also removes the
[[nodiscard]] attribute of IOFile's Open member function. There are
cases where a file may want to be opened, but have the status of it
checked at a later time.
Android and macOS have supported thread_local for quite a while, but
most importantly is that we don't even really need it. Instead of using
a thread-local buffer, we can just return a non-static buffer as a
std::string, avoiding the need for that quality entirely.
