Import posix_spawn from Gnulib.

posix_spawn is less error-prone than vfork + exec, and can make use of
system-specific optimizations like `clone' on Linux.  Import Gnulib
replacement so that we can use recent additions like
`posix_spawn_file_actions_addchdir'.

The only manual change are to admin/merge-gnulib and .gitignore.  All
other changes are due to rerunning merge-gnulib.

* admin/merge-gnulib (GNULIB_MODULES): Add posix_spawn-related
modules.
* .gitignore: Add new generated files.

1 files changed, 8 insertions, 1 deletions

diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 880dc5eef53..f1ed2da69e5 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -39,7 +39,14 @@ GNULIB_MODULES='
   getloadavg getopt-gnu getrandom gettime gettimeofday gitlog-to-changelog
   ieee754-h ignore-value intprops largefile libgmp lstat
   manywarnings memmem-simple mempcpy memrchr minmax mkostemp mktime nstrftime
-  pathmax pipe2 pselect pthread_sigmask
+  pathmax pipe2
+  posix_spawn posix_spawn_file_actions_addchdir
+  posix_spawn_file_actions_adddup2 posix_spawn_file_actions_destroy
+  posix_spawn_file_actions_init
+  posix_spawnattr_destroy posix_spawnattr_init
+  posix_spawnattr_setflags posix_spawnattr_setpgroup
+  posix_spawnattr_setsigdefault posix_spawnattr_setsigmask
+  pselect pthread_sigmask
   qcopy-acl readlink readlinkat regex
   sig2str sigdescr_np socklen stat-time std-gnu11 stdalign stddef stdio
   stpcpy strnlen strtoimax symlink sys_stat sys_time