wrapper: implement xopen()
A common usage pattern of open() is to check if it was successful, and
die() if it was not:
int fd = open(path, O_WRONLY | O_CREAT, 0777);
if (fd < 0)
die_errno(_("Could not open '%s' for writing."), path);
Implement a wrapper function xopen() that does the above so that we can
save a few lines of code, and make the die() messages consistent.
Helped-by: Torsten Bögershausen <tboegi@web.de>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>