tree fcf3b1568036c9695a25273cd2e92dec784efcc3
parent eea3906f0e2a8d3622080127d2005ff214d51383
author Gaby Baghdadi <baghdadi@ca.ibm.com> 1620837428 -0400
committer Commit Bot <commit-bot@chromium.org> 1628702774 +0000

Enable GN to build & run on z/OS

All changes are guarded in source files by OS_ZOS macro (defined
ifdef __MVS__), and in build/gen.py by platform.is_zos().

Summary of changes:
- build: add ninja template file
- gen: updates to generate the ninja build files, and add dependency
  on zoslib (https://github.com/ibmruntimes/zoslib) to use its APIs
- config: define OS_ZOS and OS_POSIX
- src: include OS host "zos" in SetSystemVarsLocked()
- src: use APIs from zoslib for thread_local impl'n, GetExePath(),
  sem_init/post/wait/destroy(), and a basic version of clock_gettime()
- src: workaround a Woz compiler bug (arg to std::pair)
- src: use utime, stat, fd_set, exclude headers
- src: use stat, mode, mktemp
- src: change to not assume O_RDONLY is 0 on all platforms (2 on z/OS)

Note: files generated by GN must be manually tagged, so they can be read:
$ find . -type f -name "*.ninja*" -exec chtag -tc819 {} \;

Change-Id: Id06e12c9ca88424a9495a5a2d1ed4e2575185196
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/11520
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>