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.

run-test.py: greatly increase the priority of 'check-code' tests As check-code is actually quite long to run for its file size, this prevent them to be scheduled too late during the test run. This reduces my typical test run from 107 seconds to 90 seconds

run-tests: allow different extra weight for slow tests The 'test-check-code-hg.t' file is not big enough to be prioritized properly. As a result my tests run often spend about 15 seconds running only it at the end of its tests run. We make the "slow" mechanism a bit smarter to adjust the extra weight of each category independently in a future patch.

ignore: refactor syntax concatenation This refactors the syntax+rule concatenation logic to be more separated. It determines the syntax and the rule separately and then puts them back together. This will help in a later patch when we want to process just the rule before it gets concatenated.

ignore: refactor file read into a function This refactors the ignore file reading code into a function so that in a future patch we can make it recursive.

import-checker: loop to get list of locally defined modules at first This is a preparation for subsequent patches, which expect that all locally defined (= mercurial specific) modules are already known before examinations. Looping twice for specified modules is a little redundant, but reasonable cost for improvement in subsequent patches.

import-checker: add xargs like mode Before this patch, "import-check.py" is invoked via "xargs" in "test-module-imports.t", but it doesn't ensure that "import-checker.py" is certainly invoked with all mercurial specific files at once. "xargs" may invoke specified command multiple times with part of arguments given from stdin: according to "xargs(1)" man page, this dividing arguments is system-dependent. This patch adds "xargs" like mode to "import-checker.py". This can ensure that "import-checker.py" is certainly invoked with all mercurial specific files at once in "test-module-imports.t". This is assumed by subsequent patches.

store: add comment in _hashencode with reason for skipping the first 5 chars

test-run-tests: fix for Python 3.5 This test now passes in both 3.5 and 2.6.

run-tests: make sure all script lines are bytes

run-tests: fix checking a line to see if it needs globbing