package/fontconfig: fix build with NLS

Add TARGET_NLS_DEPENDENCIES and host-gettext dependency to avoid the
following build failure in a per-package-directorie build with
host-cairo raised because fontconfig installs its ITS files in the wrong
directory (i.e. outside of gettext-tiny symlink):

mkdir -p /tmp/instance-0/output-1/per-package/host-cairo/host
rsync -a --link-dest=/tmp/instance-0/output-1/per-package/host-fontconfig/host/ /tmp/instance-0/output-1/per-package/host-fontconfig/host/ /tmp/instance-0/output-1/per-package/host-cairo/host
rsync -a --link-dest=/tmp/instance-0/output-1/per-package/host-freetype/host/ /tmp/instance-0/output-1/per-package/host-freetype/host/ /tmp/instance-0/output-1/per-package/host-cairo/host
rsync -a --link-dest=/tmp/instance-0/output-1/per-package/host-libglib2/host/ /tmp/instance-0/output-1/per-package/host-libglib2/host/ /tmp/instance-0/output-1/per-package/host-cairo/host
cannot delete non-empty directory: share/gettext
could not make way for new symlink: share/gettext

This only happens with per-package directories because then the rsync is
done. Otherwise the fontconfig installation will simply follow the
symlink.

The error of course exists for target as well, but doesn't occur in
autobuilders since it already fails for host.

Fixes:
 - http://autobuild.buildroot.org/results/00e29958cecfffa4e994ab549637117dd8f55c30



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>