i18n: don't restrict LINGUAS at configure time

Don't use the $LINGUAS at configure time to set ALL_LINGUAS, and let
the translations Makefile properly honor the $LINGUAS itself, which it
already does better than we do, cleanly ignoring translations it
doesn't know.

If we do set ALL_LINGUAS=$LINGUAS, it will result in a build failure if
we do not have a translation for some of the language(s) specified in
$LINGUAS, and would make it impossible to build other languages without
re-configuring.  So, just drop that part and let the build-time support
kick in.

Closes #507.

m4/geany-i18n.m4

@@ -10,11 +10,7 @@ AC_DEFUN([GEANY_I18N],
 	AC_SUBST([GETTEXT_PACKAGE])
 	AC_DEFINE_UNQUOTED([GETTEXT_PACKAGE], ["$GETTEXT_PACKAGE"], [Gettext package.])
 
-	if test -n "${LINGUAS}"; then
-		ALL_LINGUAS="${LINGUAS}"
-	else
-		ALL_LINGUAS=`cd "$srcdir/po" 2>/dev/null && ls *.po 2>/dev/null | $AWK 'BEGIN { FS="."; ORS=" " } { print $[]1 }'`
-	fi
+	ALL_LINGUAS=`cd "$srcdir/po" 2>/dev/null && ls *.po 2>/dev/null | $AWK 'BEGIN { FS="."; ORS=" " } { print $[]1 }'`
 
 	AM_GLIB_GNU_GETTEXT
 	# workaround for intltool bug (http://bugzilla.gnome.org/show_bug.cgi?id=490845)