Fixes a failure mode where git-annex sync would try to run git-annex and
complain that it failed to find it in ~/.config/git-annex/program or PATH,
when there was a git-annex in /usr/bin/, but the original one was run
from elsewhere (eg, ~/bin) and happened not to be present any longer.
Now, it will fall back to using git-annex from PATH in such a case.
Which might fail due to some version incompatability, but still better
than a misleading error message.
Also made readProgramFile only read the file, not look for git-annex in
PATH as a fallback. That fallback may have confused Assistant.Upgrade,
which really wants the value from the file.
Improve git-annex's ability to find the path to its program, especially
when it needs to run itself in another repo to upgrade it.
Some parts of the code used readProgramFile, probably because I forgot that
programPath exists.
I noticed this when a git-annex auto-upgrade failed because it was running
git-annex upgrade --autoonly, but the code to run git-annex used
readProgramFile, which happened to point to an older build of git-annex.
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.
Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.
(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
This was introduced by commit 450ee53ab6
However, the same problem could affect other calls to programPath,
specifically some on the assistant. So, I fixed it at a deeper level.
This works around horribleness in the Mavericks cpp, which falls over on
the #if when configure is running. Moving it avoids the file being built at
that point.
But it's also a location that makes sense..
