OpenBSD support for yasm.

- include the openbsd configuration for yasm
- use the correct yasm_flags on every posix system except for mac

Patch by Robert Nagy <robert.nagy@gmail.com>

BUG=
TEST=
Review URL: http://codereview.chromium.org/8348002

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8f08db25e83410e4bacd5311daf9e696042f20ec
4 files changed
tree: 17bf855530e73811a19ab838432bc09d1158d11e
  1. README.chromium
  2. source/
  3. yasm.gyp
  4. yasm_compile.gypi