Change a9fca58 made use of the O_CLOEXEC flag, which is not supported on
older Linux kernels. This change makes the use contingent on kernel
support.
Testing: I manually compiled breakpad on CentOS 5.8 running kernel
2.6.18-308.8.2.el5.centos.plusxen.
Bug: 730
Change-Id: I21dff928cfba3c156a56708913f65a0c7b5396a6
Reviewed-on: https://chromium-review.googlesource.com/498528
Reviewed-by: Mike Frysinger <vapier@chromium.org>
