po: Sync gettext-tools/po/Makevars with gettext-runtime/po/Makevars

* Makevars (PACKAGE_GNU, PO_DEPENDS_ON_POT)
(DIST_DEPENDS_ON_UPDATE_PO): New variables.
* Makevars.template (PACKAGE_GNU, PO_DEPENDS_ON_POT)
(DIST_DEPENDS_ON_UPDATE_PO): New variables.
msgl-check: Treat missing header errors as warnings

Problem reported by Richard Hughes at
<https://lists.fedoraproject.org/pipermail/devel/2014-June/199539.html>.
After <https://savannah.gnu.org/bugs/?40262>, "msgfmt -c" reports
error on missing PO headers.  However, it turned out to be too strict
for the projects using Launchpad Translations.  Let's relax the check
for the moment and wait for one or two release cycles.
* gettext-tools/src/msgl-check.c (check_header_entry): Report missing
required headers as warning, instead of error.
vala: Don't elide comments while parsing string literal

* x-vala.c (phase3_get): Use phase1_getc to read characters inside
a string literal.
build: Handle 'environ' global variable differently on cygwin x86_64

Amendment to commit c97dafde.
* tests/test-environ.c.diff: New file.
* Makefile.am (EXTRA_DIST): Add new patch.
Fix the last commit
tests: Ignore the LINGUAS envvar in msgfmt-desktop-2

Reported by Lars Wendler at:
<http://lists.gnu.org/archive/html/bug-gettext/2014-06/msg00002.html>.
* msgfmt-desktop-2: Unset the LINGUAS envvar.
desktop: Read LINGUAS file even if LINGUAS envvar is set

* msgfmt.c (get_languages): If the LINGUAS envvar is set, use it
to restrict the languages list read from the LINGUAS file, not to
extend the list.
(add_languages): Take an optional DESIRED_LANGUAGES argument.
desktop: Use logical filename as msgid location

* read-desktop.c (desktop_parse): Pass logical filename instead of
real filename to desktop_reader_handle_pair.
maint: Mention how to use the included gettext-tools to regeneate files
NEWS: Mention 0.19.1 changes
examples: Don't require msgfmt when compiling hello-c-gnome3

* hello-c-gnome3/Makefile.am (CLEANFILES): Clean hello.desktop.
(EXTRA_DIST): Add hello.desktop.in.
(MAINTAINERCLEANFILES): Add hello.desktop.in.
(hello.desktop): Move msgfmt invocation to...
(hello.desktop.in): ...here.
tests: Remove debug code from msgattrib-19
tests: Prevent autopoint tests from creating temp files in /tmp
configure: also distribute xz-compressed tarballs

* configure.ac (AM_INIT_AUTOMAKE): Add dist-xz, so that xz-compressed
.tar.xz tarballs will be distributed alongside .tar.gz ones.
autogen.sh: Use xz-compressed archive tarball

* autogen.sh: Fetch archive.dir-latest.tar.xz instead of .tar.gz.
maint: Mention xz-compressed tarball in Admin/release-steps
doc: Update the matrix

* matrix.texi: Update.
* nls.texi (STATUS): Likewise.
xgettext: Fix misrecognition of character literals in C and Vala

Problem reported by Paul Eggert at
<http://lists.gnu.org/archive/html/bug-gettext/2014-06/msg00015.html>.
* x-c.c (phase5_get): Make sure to skip contents of character constant.
* x-vala.c (phase3_get): Likewise.
msgmerge: Disable --color option in --update mode

Suggested by 林Ｖ字龍 at:
<https://lists.gnu.org/archive/html/bug-gettext/2014-06/msg00017.html>.
* msgmerge.c (main): Error out when --color and --update are
specified at the same time.
Update translations from Translation Project