Makefile: add xgettext target for *.sh files

Change the "pot" target to also extract strings from our $(SCRIPT_SH) files with xgettext(1). Note that due to Jonathan Nieder's trick of doing "mv $@+ $@" at the end of the target the "pot" target will now warn: $ make pot XGETTEXT po/git.pot po/git.pot+: warning: Charset "CHARSET" is not a portable encoding name. Message conversion to user's charset might not work. This warnings is emitted because xgettext is writing into a non-*.pot file, it's harmless however. The content that's written out is equivalent to what it would be if we were writing directly into an existing POT file with --join-existing. As part of this change I've eliminated the && chain between xgettext calls, this is incompatible with $(QUIET_XGETTEXT), if the && is left in it'll emit: /bin/sh: @echo: not found Since it's redundant (the Makefile will stop if there's an error) I've removed it altogether. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>