This is needed to avoid regressions relative to the perl version because
the perl version failed, due to a missing /, to properly examine two of
the paths, one of which often yields the same filename as the original
file (but whose CRC will fail).
I've tested that this CRC calculation succeeds in cases where it should
succeed.
The observed CRC check failures (so far) on my Ubuntu 14.04 system are
the following links:
/lib/x86_64-linux-gnu/libc.so.6 -> /lib/x86_64-linux-gnu/libc-2.19.so
/lib/x86_64-linux-gnu/libpthread.so.0 -> /lib/x86_64-linux-gnu/libpthread-2.19.so
/usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0 -> /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0.2400.23
/usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0 -> /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23
which succeed on a later possibility in /usr/lib/debug/. But optimizing
to check f != file before checking the CRC wouldn't help because of the
naming differences due to symlinks, so I didn't bother. If we ever want
to optimize away the time doing the CRC checks for these failures, we
could do so by checking if the files are the same path *after* resolving
symlinks.
DONTBUILD
Sylvestre Ledru
Nicholas Nethercote
L. David Baron
Ed Morley
Andrew McCreight