Merge qt_error_string and QSystemError

This removes a lot of duplicated code that existed in both qglobal.cpp
and qsystemerror.cpp, including the hack to get the correct strerror_r
signature.

This removes the incorrect use of EACCES, EMFILE, ENOENT, and ENOSPC
from qt_error_string on Windows. qt_error_string is supposed to be used
only with Win32 error codes from GetLastError(), despite there being a
lot of uses in cross-platform and even Windows-specific code that pass
errno constants.

It may or may not work: that depends on whether the constants happen to
match. ENOENT matches ERROR_FILE_NOT_FOUND and one could argue that
ENOSPC matching ERROR_OUT_OF_PAPER is acceptable, but EMFILE isn't the
same as ERROR_BAD_LENGTH nor is EACCES, ERROR_INVALID_DATA.

Change-Id: I1eba2b016de74620bfc8fffd14cccb7f77f4b510
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions