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