Log Message:
Update to 1.4.15:

* Noteworthy changes in release 1.4.15 (2010-08-31) [stable]

** Fix regression introduced in 1.4.9b where the `format' builtin could
   crash on an invalid format string.

** Fix compilation against newer glibc, and on AIX 7.1BETA.

** A number of portability improvements inherited from gnulib.