Add support for pipe2() on Linux.

* configure.in: Test for working pipe2().

* file_io/unix/pipe.c (file_pipe_create): Use pipe2(,O_NONBLOCK) if
  APR_FULL_NONBLOCK is requested.

* test/testpipe.c (nonblock_pipe): New test.

Github: closes #55


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1917641 13f79535-47bb-0310-9956-ffa450edef68
3 files changed