Merge branch 'fk/use-kwset-pickaxe-grep-f'

* fk/use-kwset-pickaxe-grep-f:
  obstack: Fix portability issues
  Use kwset in grep
  Use kwset in pickaxe
  Adapt the kwset code to Git
  Add string search routines from GNU grep
  Add obstack.[ch] from EGLIBC 2.10

diff --cc Makefile
Simple merge

diff --cc grep.c
Simple merge