l10n: zh_CN.po: translate 46 new messages (2229t0f0u)

Translations for git v2.0.0-rc0.  Also correct translatioins on relative
date in date.c with help from Brian Gesiak ($gmane/246390).

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
i18n: fix uncatchable comments for translators in date.c

Comment for l10n translators can not be extracted by xgettext if it
is not right above the l10n tag.  Moving the comment right before
the l10n tag will fix this issue.

Reported-by: Brian Gesiak <modocache@gmail.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
i18n: remove obsolete comments for translators in diffstat generation

Since we do not translate diffstat any more, remove the obsolete comments.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
i18n: only extract comments marked with "TRANSLATORS:"

When extract l10n messages, we use "--add-comments" option to keep
comments right above the l10n messages for references.  But sometimes
irrelevant comments are also extracted.  For example in the following
code block, the comment in line 2 will be extracted as comment for the
l10n message in line 3, but obviously it's wrong.

        { OPTION_CALLBACK, 0, "ignore-removal", &addremove_explicit,
          NULL /* takes no arguments */,
          N_("ignore paths removed in the working tree (same as
          --no-all)"),
          PARSE_OPT_NOARG, ignore_removal_cb },

Since almost all comments for l10n translators are marked with the same
prefix (tag): "TRANSLATORS:", it's safe to only extract comments with
this special tag.  I.E. it's better to call xgettext as:

        xgettext --add-comments=TRANSLATORS: ...

Also tweaks the multi-line comment in "init-db.c", to make it start with
the proper tag, not "* TRANSLATORS:" (which has a star before the tag).

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
i18n: mention "TRANSLATORS:" marker in Documentation/CodingGuidelines

These comments have to have "TRANSLATORS: " at the very beginning
and have to deviate from the usual multi-line comment formatting
convention.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
blame: fix broken time_buf paddings in relative timestamp

Command `git blame --date relative` aligns the date field with a
fixed-width (defined by blame_date_width), and if time_str is shorter
than that, it adds spaces for padding.  But there are two bugs in the
following codes:

        time_len = strlen(time_str);
        ...
        memset(time_buf + time_len, ' ', blame_date_width - time_len);

 1. The type of blame_date_width is size_t, which is unsigned.  If
    time_len is greater than blame_date_width, the result of
    "blame_date_width - time_len" will never be a negative number, but a
    really big positive number, and will cause memory overwrite.

    This bug can be triggered if either l10n message for function
    show_date_relative() in date.c is longer than 30 characters, then
    `git blame --date relative` may exit abnormally.

 2. When show blame information with relative time, the UTF-8 characters
    in time_str will break the alignment of columns after the date field.
    This is because the time_buf padding with spaces should have a
    constant display width, not a fixed strlen size.  So we should call
    utf8_strwidth() instead of strlen() for width calibration.

Helped-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
blame: dynamic blame_date_width for different locales

When show date in relative date format for git-blame, the max display
width of datetime is set as the length of the string "Thu Oct 19
16:00:04 2006 -0700" (30 characters long).  But actually the max width
for C locale is only 22 (the length of string "x years, xx months ago").
And for other locale, it maybe smaller.  E.g. For Chinese locale, only
needs a half (16-character width).

Set blame_date_width as the display width of _("4 years, 11 months
ago"), so that translators can make the choice.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>