grep: Upgrade to version 2.9

grep: Upgrade to version 2.9

Release 2.9 (2011-06-21) [stable]
Release 2.8 (2011-05-13) [stable]

Bug Fixes
===================
1. echo c|grep '[c]' would fail for any c in 0x80..0xff,
   and in many locales.
   E.g., printf '\xff\n'|grep "$(printf '[\xff]')" || echo FAIL
   would print FAIL rather than the required matching line.
   [bug introduced in grep-2.6]

2. grep's interpretation of range expression is now more consistent with
   that of other tools.  [bug present since multi-byte character set
   support was introduced in 2.5.2, though the steps needed to reproduce
   it changed in grep-2.6]

3. grep erroneously returned with exit status 1 on some memory allocation
   failure. [bug present since "the beginning"]

4. grep no longer clobbers heap for an ERE like '(^| )*( |$)'
   [bug introduced in grep-2.6]

5. grep is faster on regular expressions that match multibyte characters
   in brackets (such as '[áéíóú]').

6. echo c|grep '[c]' would fail for any c in 0x80..0xff, with a uni-byte
   encoding for which the byte-to-wide-char mapping is nontrivial.  For
   example, the ISO-88591 locales are not affected, but ru_RU.KOI8-R is.
   [bug introduced in grep-2.6]

7. grep -P no longer aborts when PCRE's backtracking limit is exceeded
   Before, echo aaaaaaaaaaaaaab |grep -P '((a+)*)+$' would abort.  Now,
   it diagnoses the problem and exits with status 2.