Re: master fails to build on FreeBSD when ACL support is on

[Paul Eggert]

Joseph Mingrone wrote:
> the problem only seems to occur when /tmp supports ACLs,
> but $WRKDIR (location where the tarball is extracted and the build
> occurs) does not.

The problem occurs because (rename-file A B) signals an error if A has ACLs and 
B's file system does not support ACLs. This is because rename-file calls 
(copy-file A B nil t t t) and that last "t" tells copy-file to copy ACLs.

Creating a temporary file right next to the original file should fix the problem 
for bytecomp.el, since rename-file won't be crossing file system boundaries.

The more-general question is whether rename-file should fail in this situation. 
It is a bit of an edge case. From code inspection it appears that GNU 'mv A B' 
issues a warning diagnostic but does not fail (i.e., it does not exit with 
nonzero status).