git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66041 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* I believe this should be default behavior, see [Feature #2250].
* Now make test-spec MSPECOPT='-R100 spec/ruby/library/socket' works fine.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64454 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

getgroups(2) may return a GID list that includes duplicated GIDs.
The behavior is totaly depends on what OS is used.

This commit fixes the example of Process.groups so that the example
is independent of this OS-dependent features.

Additonaly, this commit adds the description of such system-dependent
characteristics of Process.groups.

[ruby-dev:50603] [Bug #14969]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64265 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Non-parallel "make test-spec" caused
spec/ruby/core/process/wait2_spec.rb failures because mspec
uses "exec" in single-process mode, so there's no chance
the post-exec state could know about the MJIT child process
from its pre-exec state.

[ruby-core:87846] [Bug #14867]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63877 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

This is not working with cppflags="-DMJIT_FORCE_ENABLE" on my machine.

```
$ make test-spec
$ /home/k0kubun/src/github.com/ruby/ruby-svn/.ruby-force/miniruby -I/home/k0kubun/src/github.com/ruby/ruby-svn/lib /home/k0kubun/src/github.com/ruby/ruby-svn/tool/runruby.rb --archdir=/home/k0kubun/src/github.com/ruby/ruby-svn/.ruby-force --extout=.ext -- /home/k0kubun/src/github.com/ruby/ruby-svn/spec/mspec/bin/mspec-run -B ../spec/default.mspec
ruby 2.6.0dev (2018-07-07 trunk 63874) +JIT [x86_64-linux]
[| | ================  40%                    | 00:02:03]      0F      0E leaked before wait2 specs: [[31406, #<Process::Status: pid 31406 exit 0>]]

1)
An exception occurred during: before :all FAILED
Expected [[31406, #<Process::Status: pid 31406 exit 0>]] to be empty
/home/k0kubun/src/github.com/ruby/ruby-svn/spec/ruby/core/process/wait2_spec.rb:18:in `block (3 levels) in <top (required)>'
/home/k0kubun/src/github.com/ruby/ruby-svn/spec/ruby/core/process/wait2_spec.rb:16:in `block (2 levels) in <top (required)>'
/home/k0kubun/src/github.com/ruby/ruby-svn/spec/ruby/core/process/wait2_spec.rb:3:in `<top (required)>'
[- | ==================100%================== | 00:00:00]      1F      0E

Finished in 103.288794 seconds

3607 files, 28545 examples, 208272 expectations, 1 failure, 0 errors, 0 tagged
uncommon.mk:777: recipe for target 'yes-test-spec' failed
make: *** [yes-test-spec] Error 1
```

Let me skip this for now and enable MJIT CI again.

Related to Bug#14867

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63876 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Reading win32/win32.c waitpid implementation, maybe waitpid(-1, ...)
on that platform will never conflict with mjit use of waitpid.

In any case, I've added WAITPID_USE_SIGCHLD macro to vm_core.h
so it can be easy for Linux/BSD users to test (hopefully!)
win32-compatible code.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63855 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

The change is unstable on Windows. Please re-commit it when it correctly
supports Windows.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63852 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

It is possible to have both MJIT and normal child processes
alive, so we cannot set ECHILD based on such a guess.  We can
still elide waitpid(PID <= 0) calls if we have callers in
vm->waiting_pids, however.

For specs, ensure Process.waitall does not leak MJIT
PIDs to Rubyspace.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63764 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

This reverts r63731 (commit 359dd59db2512d801bb983f98bede4fc598f139a).

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63760 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

until [Bug #14867] is fixed. I want to start running CI with MJIT
enabled before fixing the problem.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63731 b2dd03c8-39d4-4d8f-98ff-823fe69b080e