RTEMS and LibBSD both provide competing pipe() interfaces

RTEMS provides a pipe() call in cpukit/libfs/src/pipe/pipe.c and LibBSD also provides a call in rtemsbsd/rtems/rtems-bsd-syscall-api.c. We should not have competing interfaces.

The selection of the version you get depends on the link order and the linker version. The RTEMS 6 linker seems to have a different preference to RTEMS 5. Apart from this fragility LibBSD should not be providing this interface.

A LibBSD pipe() is problematic for a number of reasons and so I am going to remove the call from it.

If LibBSD support is needed it needs to be via a file system op handles like all other file system interfaces for descriptor based access. I will not be adding this support.

The removal of pipe() from LibBSD removes the kqueue support for pipes. See the test selectpollkqueue01. If this support is needed please contact the RTEMS developers.