install not atomic

[Ralf Wildenhues]

Hello bug-coreutils readers,

a recent GCC bug report[1] the GNU install program is not atomic; i.e.,
when you
  install file $dest & install file $dest

then one of them may fail.  For reproducability purposes, use several
large files, and call in a loop.

I suppose it's fine for install to have this limitation, as it's
arguably a bug (or limitation) in the build system, and there is no
standard or documentation stating otherwise, but the behavior was
sufficiently surprising to me that I thought I'd write about it here
nonetheless.

Cheers,
Ralf

[1] Excerpt from one of the logs from Gary Funck's report,
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42980>:
 /usr/bin/install -c -m 644  ssp/ssp.h gcc/src/libssp/ssp/string.h 
gcc/src/libssp/ssp/stdio.h gcc/src/libssp/ssp/unistd.h 
'gcc/bld/struct/rls/usr/lcoal/lib/gcc/x86_64-unknown-linux-gnu/4.5.0/include/ssp'
 /usr/bin/install -c -m 644  ssp/ssp.h gcc/src/libssp/ssp/string.h 
gcc/src/libssp/ssp/stdio.h gcc/src/libssp/ssp/unistd.h 
'gcc/bld/struct/rls/usr/lcoal/lib/gcc/x86_64-unknown-linux-gnu/4.5.0/include/ssp'
[...]
/usr/bin/install: cannot create regular file 
`gcc/bld/struct/rls/usr/lcoal/lib/gcc/x86_64-unknown-linux-gnu/4.5.0/include/ssp/ssp.h':
 File exists