* thread_pthread.c (gvl_init): Reset gvl.wait_yield explicitly when
  fork()ing. Patch by Apollon Oikonomopoulos. Thanks!
  [Bug #7693][ruby-core:51424]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38819 b2dd03c8-39d4-4d8f-98ff-823fe69b080e