merge revision(s) 5c7af72304d0ad33cd3f21b24a4bc44e8acd5b2c,d650b17686d49c2ce8e6a87039861154e93d4621: [Backport #18497]

    Assuming EXIT_SUCCESS equals 0 is not portable

    ---
     test/ruby/test_fiber.rb | 6 +++---
     1 file changed, 3 insertions(+), 3 deletions(-)

    `rb_fiber_terminate` must not return [Bug #18497]

    In a forked process from a fiber, the fiber becomes the only
    fiber, `fiber_switch` does nothing as there is no other fibers,
    `rb_fiber_terminate` does not terminate the fiber.  In that case,
    reaches the end of `fiber_entry` finaly, which is declared as
    "COROUTINE" and should never return.
    ---
     cont.c                     |  3 ++-
     eval_intern.h              |  2 +-
     test/fiber/test_process.rb | 15 +++++++++++++++
     test/ruby/test_fiber.rb    |  5 +++++
     4 files changed, 23 insertions(+), 2 deletions(-)

    note that only backported a part of above patch because of incompatibility
    of ruby_2_7.

1 files changed, 3 insertions, 3 deletions

diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index a7ed9ac7e0..20436eca69 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -318,7 +318,7 @@ class TestFiber < Test::Unit::TestCase
                 Fiber.new {}.transfer
                 Fiber.new { Fiber.yield }
               end
-              exit!(0)
+              exit!(true)
             end
           }.transfer
           _, status = Process.waitpid2(xpid)
@@ -327,8 +327,8 @@ class TestFiber < Test::Unit::TestCase
       end.resume
     end
     pid, status = Process.waitpid2(pid)
-    assert_equal(0, status.exitstatus, bug5700)
-    assert_equal(false, status.signaled?, bug5700)
+    assert_not_predicate(status, :signaled?, bug5700)
+    assert_predicate(status, :success?, bug5700)
   end
 
   def test_exit_in_fiber