In this PR, the following changes were made:
1. Replaced `raise newException(OSError, osErrorMsg(errno))` in batches
with `raiseOSError(errcode)`.
2. Replaced `newException(OSError, osErrorMsg(errno))` in batches with
`newOSError(errcode)`.
There are still some places that have not been replaced. After checking,
they are not system errors in the traditional sense.
```nim
proc dlclose(lib: LibHandle) =
raise newException(OSError, "dlclose not implemented on Nintendo Switch!")
```
```nim
if not fileExists(result) and not dirExists(result):
# consider using: `raiseOSError(osLastError(), result)`
raise newException(OSError, "file '" & result & "' does not exist")
```
```nim
proc paramStr*(i: int): string =
raise newException(OSError, "paramStr is not implemented on Genode")
```
(cherry picked from commit 39fbd30513)
47f1ab7b97