Fix link errors related to C99-style extern inline.

After recent C99-style extern inline changes in gnulib, functions
defined in xsize.h are now declared as "extern inline".  That means
the libraries using those functions need to be linked to xsize.o.
Remove references to non-existing COPYING.LIB-2.*.
Fix link in '@opindex' pointing to msgcat.
Fix typo in msgfmt.texi.
Determine Woe32 C symbol prefix at configure time.
Update after gnulib changed.
Remove unnecessary step from Admin/release-steps.
gettextize: substitute PATH_SEPARATOR at configure time
gettextize: extract macro directories from configure.ac
Updated translations.
Fix the last commit.
gettextize: Use autoconf trace to detect auxdir and m4dir
autopoint: extract macro directories from configure.ac
po-mode: make (po-check-file-header) optional (bug #30835)

po-mode would always overwrite the PO Header Entry when editing *.po
files. This isn't always desired behavior as noted in bug #30835 so
it's now customizable.

It can be customized through the po-auto-update-file-header variable,
which can be t, nil or 'ask. It's t by default to preserve the old
default behavior.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
po-mode: Properly highlight C format strings with parameter positions
Update copyright year.
Update copyright year.
Merge branch 'maint'
Add 'autosprintf::operator='.
Update list of copyright assignments.