The "highlight" binary can, in some cases, determine the language type
by the means of file contents, for example the shebang in the first line
for some scripting languages.  Make use of this autodetection for files
which syntax is not known by gitweb.  In that case, pass the blob
contents to "highlight --force"; the parameter is needed to make it
always generate HTML output (which includes HTML-escaping).

Although we now run highlight on files which do not end up highlighted,
performance is virtually unaffected because when we call highlight, it
is used for escaping HTML.  In the case that highlight is used, gitweb
calls sanitize() instead of esc_html(), and the latter is significantly
slower (it does more, being roughly a superset of sanitize()).  Simple
benchmark comparing performance of 'blob' view of files without syntax
highlighting in gitweb before and after this change indicates ±1%
difference in request time for all file types.  Benchmark was performed
on local instance on Debian, using Apache/2.4.23 web server and CGI.

Document the feature and improve syntax highlight documentation, add
test to ensure gitweb doesn't crash when language detection is used.

Signed-off-by: Ian Kelling <ian@iankelling.org>
Acked-by: Jakub Narębski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Ian Kelling <ian@iankelling.org>
Acked-by: Jakub Narębski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>

"git gc --aggressive" used to limit the delta-chain length to 250,
which is way too deep for gaining additional space savings and is
detrimental for runtime performance.  The limit has been reduced to
50.

* jk/reduce-gc-aggressive-depth:
  gc: default aggressive depth to 50

Even when "git pull --rebase=preserve" (and the underlying "git
rebase --preserve") can complete without creating any new commit
(i.e. fast-forwards), it still insisted on having a usable ident
information (read: user.email is set correctly), which was less
than nice.  As the underlying commands used inside "git rebase"
would fail with a more meaningful error message and advice text
when the bogus ident matters, this extra check was removed.

* jk/rebase-i-drop-ident-check:
  rebase-interactive: drop early check for valid ident

More i18n.

* va/i18n:
  i18n: update-index: mark warnings for translation
  i18n: show-branch: mark plural strings for translation
  i18n: show-branch: mark error messages for translation
  i18n: receive-pack: mark messages for translation
  notes: spell first word of error messages in lowercase
  i18n: notes: mark error messages for translation
  i18n: merge-recursive: mark verbose message for translation
  i18n: merge-recursive: mark error messages for translation
  i18n: config: mark error message for translation
  i18n: branch: mark option description for translation
  i18n: blame: mark error messages for translation

"git format-patch --base=..." feature that was recently added
showed the base commit information after "-- " e-mail signature
line, which turned out to be inconvenient.  The base information
has been moved above the signature line.

* jt/format-patch-base-info-above-sig:
  format-patch: show base info before email signature

Performance tests done via "t/perf" did not use the same set of
build configuration if the user relied on autoconf generated
configuration.

* ks/perf-build-with-autoconf:
  t/perf/run: copy config.mak.autogen & friends to build area

Code cleanup.

* mr/vcs-svn-printf-ulong:
  vcs-svn/fast_export: fix timestamp fmt specifiers

"git diff -W" output needs to extend the context backward to
include the header line of the current function and also forward to
include the body of the entire current function up to the header
line of the next one.  This process may have to merge to adjacent
hunks, but the code forgot to do so in some cases.

* rs/xdiff-merge-overlapping-hunks-for-W-context:
  xdiff: fix merging of hunks with -W context and -u context