Merge with mpm.

Teach walk code about absolute paths. The first consequence of this is that absolute and relative paths now all work in the same way. The second is that paths that lie outside the repository now cause an error to be reported, instead of something arbitrary and expensive being done. Internally, all of the serious work is in the util package. The new canonpath function takes an arbitrary path and either returns a canonical path or raises an error. Because it needs to know where the repository root is, it must be fed a repository or dirstate object, which has given commands.matchpats and friends a new parameter to pass along. The util.matcher function uses this to canonicalise globs and relative path names. Meanwhile, I've moved the Abort exception from commands to util, and killed off the redundant util.CommandError exception.

Kill dead function.

Fix debugwalk when there's nothing to walk.

Allow Mercurial to build on HP-UX 11 Temporary fix to allow Mercurial to build on HP-UX 11, as the C compiler on HP-UX 11 doesn't support 'inline' qualifier. The '__inline' qualifier seemed to be supported, but not without first resolving other associated issues.

Merge with TAH

Cleanup after previous changes: - there are only two states for the exec bit, so no need to override it. - file_ variable is only once now, so it self.file(f) can be used directly.