testcase: split BIN_PROGRAMS line by line

    modified:   testcase/Makefile
Implement pipe() with a non-blocking mode

    modified:   check.cmd
    new file:   io/non-block-pipe.c
    new file:   io/non-block-pipe.h
    modified:   testcase/Makefile
    new file:   testcase/non-block-pipe-1.c
    new file:   testcase/non-block-pipe-2.c