factotum: use try/except/finally

check-code: drop try/except/finally check

util.h: kill no longer needed definitions for Python < 2.6 see e1fb276d4619

merge with stable

setup: integrate osutil C extension into extmodules initialization

setup: move osutil_ldflags logic to before extmodules definition

setup: kill pure hack for osutil on Windows for Python 2.4 see e1fb276d4619

windows: add comment in normcase() see also 3c5e818ac679

rebase: clear merge when aborting before any rebasing (issue4661) The check of the inrebase function was not correct, and it failed to consider the situation in which nothing has been rebased yet, *and* the working dir had been updated away from the initial revision. But this is easy to fix. Given the rebase state, we know exactly where we should be standing: on the first unrebased commit. We check that instead. I also took the liberty to rename the function, as "inrebase" doesn't really describe the situation: we could still be in a rebase state yet the user somehow forcibly updated to a different revision. We also check that we're in a merge state, since an interrupted merge is the only "safe" way to interrupt a rebase. If the rebase got interrupted by power loss or whatever (so there's no merge state), it's still safer to not blow away the working directory.

test-rebase-abort: add test from issue4009 The fix for issue4009, namely fe78eb7bcca0, introduced issue4661. Let's make sure that the fix for issue4661 will not reintroduce issue4009.