revsetlang: add a hint for more useful parse errors This logic is largely based on the similar logic added to template error messages in D2608 and D2609, but with a few tweaks based on how revsets actually work. Differential Revision: https://phab.mercurial-scm.org/D2619

setup: ignore extension load failures when finding working hg Previously, `make local` would fail if any extension was not properly loading. Differential Revision: https://phab.mercurial-scm.org/D2589

profile: colorize output on Windows Previously, the ANSI codes were printed to the screen, throwing off the alignment. We could probably do this unconditionally, but it's kind of a hack, so I figured I'd limit the scope.

dispatch: don't clamp the range of the exit code twice We already limit the range to (0, 255) in the call to sys.exit(). The duplicated operation can't possibly be hurting us, but let's clean it up to avoid confusion.

bdiff: avoid pointer arithmetic on void* MSVC 2008 complains: mercurial/cext/bdiff.c(106) : error C2036: 'void *' : unknown size mercurial/cext/bdiff.c(107) : error C2036: 'void *' : unknown size Maybe it's a gcc extension? https://stackoverflow.com/questions/37460579/error-c2036-void-unknown-size

fuzz: add a quick README to try and document how to test new fuzzers Differential Revision: https://phab.mercurial-scm.org/D2633

fuzz: add a fuzzer for xdiff Based entirely on the fuzzer for bdiff. Differential Revision: https://phab.mercurial-scm.org/D2632

tests: add tests about diff quality These show the differences between bdiff and xdiff. Differential Revision: https://phab.mercurial-scm.org/D2604

run-tests: allow #require inside #if Used by the next patch. Differential Revision: https://phab.mercurial-scm.org/D2605

mdiff: add a config option to use xdiff algorithm The `experimental.xdiff` will affect the default diffopts and make mdiff use the xdiff algorithm for better diff quality. Differential Revision: https://phab.mercurial-scm.org/D2603