Fix testcases regarding O_NONBLOCK on parisc/hppa architecture

[hdeller]

On the parisc/hppa architecture, the O_NONBLOCK constant can be either
000200000 or 000200004, depending on the Linux kernel and glibc version
on which the binary is running.
Background of this can be read in this upstream Linux kernel patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=75ae04206a4d0e4f541c1d692b7febd1c0fdb814

The tor testcases fail because of this, because function
fd_is_nonblocking() checks hard against the O_NONBLOCK value, while it's
sufficient if it would only check if one of the bits is set.

Fix this trivial issue by just comparing if the returned file descriptor flag
and'ed with O_NONBLOCK is non-zero.

As reference, a failing build on parisc/hppa can be seen here:
https://buildd.debian.org/status/fetch.php?pkg=tor&arch=hppa&ver=0.4.4.6-1%2Bb1&stamp=1612225628&raw=0

[coveralls]

Pull Request Test Coverage Report for Build 10755

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 13 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.02%) to 64.501%

---

Files with Coverage Reduction	New Missed Lines	%
src/feature/dirauth/shared_random.c	4	85.0%
src/feature/dirauth/dirvote.c	9	68.12%

Totals
Change from base Build 10750:	-0.02%
Covered Lines:	52057
Relevant Lines:	80707

---

💛 - Coveralls

[weaselp]

If changing the constants is a thing that happens, I wonder if the return (flags & FD_CLOEXEC) == FD_CLOEXEC; from a few lines before that should be equally changed.

[hdeller]

On 2/3/21 9:01 AM, weasel wrote: If changing the constants is a thing that happens,

Usually it doesn't happen. But it might, as can be seen in this case.

I wonder if the |return (flags & FD_CLOEXEC) == FD_CLOEXEC;| from a few lines before that should be equally changed.

Yes, this line should be changed in the same manner too. I just didn't sent a patch for that, because I wanted to concentrate on the O_NONBLOCK only in the first step. Helge