Compilation fix for a recent topic in 'master'.

* ye/http-accept-language:
  gettext.c: move get_preferred_languages() from http.c

Calling setlocale(LC_MESSAGES, ...) directly from http.c, without
including <locale.h>, was causing compilation warnings.  Move the
helper function to gettext.c that already includes the header and
where locale-related issues are handled.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

We did not check the curl library version before using
CURLOPT_PROXYAUTH feature that may not exist.

* tc/missing-http-proxyauth:
  http: support curl < 7.10.7

Using environment variable LANGUAGE and friends on the client side,
HTTP-based transports now send Accept-Language when making requests.

* ye/http-accept-language:
  http: add Accept-Language header if possible

A broken pack .idx file in the receiving repository prevented the
dumb http transport from fetching a good copy of it from the other
side.

* jk/dumb-http-idx-fetch-fix:
  dumb-http: do not pass NULL path to parse_pack_index

Mark file-local symbols as "static", and drop functions that nobody
uses.

* jc/unused-symbols:
  shallow.c: make check_shallow_file_for_update() static
  remote.c: make clear_cas_option() static
  urlmatch.c: make match_urls() static
  revision.c: make save_parents() and free_saved_parents() static
  line-log.c: make line_log_data_init() static
  pack-bitmap.c: make pack_bitmap_filename() static
  prompt.c: remove git_getpass() nobody uses
  http.c: make finish_active_slot() and handle_curl_result() static

Commit dd61399 introduced support for http proxies that require
authentication but it relies on the CURL_PROXYAUTH option which was
added in curl 7.10.7.
This makes sure proxy authentication is only enabled if libcurl can
support it.

Signed-off-by: Tom G. Christensen <tgc@statsbiblioteket.dk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Add an Accept-Language header which indicates the user's preferred
languages defined by $LANGUAGE, $LC_ALL, $LC_MESSAGES and $LANG.

Examples:
  LANGUAGE= -> ""
  LANGUAGE=ko:en -> "Accept-Language: ko, en;q=0.9, *;q=0.1"
  LANGUAGE=ko LANG=en_US.UTF-8 -> "Accept-Language: ko, *;q=0.1"
  LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *;q=0.1"

This gives git servers a chance to display remote error messages in
the user's preferred language.

Limit the number of languages to 1,000 because q-value must not be
smaller than 0.001, and limit the length of Accept-Language header to
4,000 bytes for some HTTP servers which cannot accept such long header.

Signed-off-by: Yi EungJun <eungjun.yi@navercorp.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Once upon a time, dumb http always fetched .idx files
directly into their final location, and then checked their
validity with parse_pack_index. This was refactored in
commit 750ef42 (http-fetch: Use temporary files for
pack-*.idx until verified, 2010-04-19), which uses the
following logic:

  1. If we have the idx already in place, see if it's
     valid (using parse_pack_index). If so, use it.

  2. Otherwise, fetch the .idx to a tempfile, check
     that, and if so move it into place.

  3. Either way, fetch the pack itself if necessary.

However, it got step 1 wrong. We pass a NULL path parameter
to parse_pack_index, so an existing .idx file always looks
broken. Worse, we do not treat this broken .idx as an
opportunity to re-fetch, but instead return an error,
ignoring the pack entirely. This can lead to a dumb-http
fetch failing to retrieve the necessary objects.

This doesn't come up much in practice, because it must be a
packfile that we found out about (and whose .idx we stored)
during an earlier dumb-http fetch, but whose packfile we
_didn't_ fetch. I.e., we did a partial clone of a
repository, didn't need some packfiles, and now a followup
fetch needs them.

Discovery and tests by Charles Bailey <charles@hashpling.org>.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

They used to be used directly by remote-curl.c for the smart-http
protocol. But they got wrapped by run_one_slot() in beed336 (http:
never use curl_easy_perform, 2014-02-18).  Any future users are
expected to follow that route.

Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>