merge revision(s) 50423: [Backport #11733]
* ext/-test-/file/fs.c: need to include sys/statvfs.h to use statvfs(). * ext/-test-/file/extconf.rb: check the existence of sys/statvfs.h
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@52973 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 50423: [Backport #11733]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@52973 b2dd03c8-39d4-4d8f-98ff-823fe69b080e