This is important to issue sync requests for written-to files.
As the closing must be performed by an atexit handler, it happens at a
time _after_ libc plugins are destructed. Consequently an FD allocated
by such a plugin results in a close error, which in turn, does not
destruct the FD. We ultimatedly end up in an infinte loop of
re-attempting the close. For this reason, the patch changes 'close' to
be robust against this special case.
This is generally not a problem because libc plugins are phased out.
However, at present, the libc_noux plugin is still important. With the
changed 'close' in place, there occurred an error message "Error: close:
close not implemented" at the exit of each noux program. This patch
removes the error printing from the libc plugin mechansim to avoid this
noise. The error messages are not important anyway because the
deprecation of the libc plugin interface.
Issue #3578
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
