filemerge: split internal merge into api entry point and internal helper
This is a step toward adding 'union merge' to the internal merge tool.
'union merge' is a merge strategy which adds both left and right hand side
of a conflict region. Git implements this merge strategy which is very
practical to have for merging to e.g. the Changelog file.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.