Fix bug #14386: updatedb relies on mktemp, which is not portable.
* locate/updatedb.sh (make_tempdir): new function, works around the possible absence of mktemp. We now create the file list and the bigrams file in a temporary directory. Also add some quoting for a few shell variables. Update the copyright years. * locate/testsuite/locate.gnu/oldformat.exp: Add a test case which uses the old database format, in order to exercise our mktemp replacement. * locate/testsuite/Makefile.am (EXTRA_DIST_EXP): Ship this new file. * locate/testsuite/locate.gnu/oldformat.xo: The expected output for the new test. * locate/testsuite/Makefile.am (EXTRA_DIST_XO): Ship this new file. * NEWS: Mention this bugfix.