function reBasenamePosix() {
	return /^(?:\/?|)(?:[\s\S]*?)((?:\.{1,2}|[^\/]+?|)(?:\.[^.\/]*|))(?:[\/]*)$/; // eslint-disable-line no-useless-escape
}
Returns a regular expression to capture the last part of a POSIX path.

@returns {RegExp} regular expression

@example
var RE_BASENAME_POSIX = reBasenamePosix();
var base = RE_BASENAME_POSIX.exec( 'foo/bar/index.js' )[ 1 ];
// returns 'index.js'