Avoid uninitialized result in sem_open when file does not exist HEAD master

A static analyzer apparently reported an uninitialized use of the
variable result in sem_open in the case where the file is required to
exist but does not exist.

The report appears to be correct; set result to SEM_FAILED in that
case, and add a test for it.

Note: the test passes for me even without the sem_open fix, I guess
because result happens to get value SEM_FAILED (i.e. 0) when
uninitialized.

Tested for x86_64.

0 files changed, 0 insertions, 0 deletions