This implements a naive version of `getline` because Windows does not
have `getline`. Given the fact that `FILE` has buffered IO, calling
`fgetc` in a loop is not as big of a performance hazard as it might seem
at first glance.
The proper solution to this would of course be to have our own buffered
IO so we are fully in charge of the buffer. In this situation we could
check the entire buffer for a newline at once instead of char by char.
However that is not going to happen for the near future so I propose we
stay with this implementation. If reading individual lines of a file
does truly end up being the performance bottle neck we have already
won^^.
This PR:
- changes the implementation of `readBinFile` and `readFile` to only
require two system calls (`stat` + `read`) instead of one `read` per
1024 byte chunk.
- fixes a bug where `Handle.getLine` would get tripped up by a NUL
character in the line and cut the string off. This is caused by the fact
that the original implementation uses `strlen` and `lean_mk_string`
which is the backer of `mk_string` does so as well.
- fixes a bug where `Handle.putStr` and thus by extension `writeFile`
would get tripped up by a NUL char in the line and cut the string off.
Cause here is the use of `fputs` when a NUL char is possible.
Closes: #4891Closes: #3546Closes: #3741
