Merge branch 'ab/retire-pcre1'

The support for deprecated PCRE1 library has been dropped.

* ab/retire-pcre1:
  Remove support for v1 of the PCRE library
  config.mak.uname: remove redundant NO_LIBPCRE1_JIT flag

diff --cc Makefile
Simple merge

diff --cc grep.c
Simple merge

diff --cc grep.h
Simple merge

diff --cc t/test-lib.sh
Simple merge