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

Makefile

@@ -515,6 +515,7 @@ LIB_H += commit.h
 LIB_H += compat/bswap.h
 LIB_H += compat/cygwin.h
 LIB_H += compat/mingw.h
+LIB_H += compat/obstack.h
 LIB_H += compat/win32/pthread.h
 LIB_H += compat/win32/syslog.h
 LIB_H += compat/win32/sys/poll.h
@@ -533,6 +534,7 @@ LIB_H += graph.h
 LIB_H += grep.h
 LIB_H += hash.h
 LIB_H += help.h
+LIB_H += kwset.h
 LIB_H += levenshtein.h
 LIB_H += list-objects.h
 LIB_H += ll-merge.h
@@ -594,6 +596,7 @@ LIB_OBJS += cache-tree.o
 LIB_OBJS += color.o
 LIB_OBJS += combine-diff.o
 LIB_OBJS += commit.o
+LIB_OBJS += compat/obstack.o
 LIB_OBJS += config.o
 LIB_OBJS += connect.o
 LIB_OBJS += convert.o
@@ -623,6 +626,7 @@ LIB_OBJS += hash.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.o
 LIB_OBJS += ident.o
+LIB_OBJS += kwset.o
 LIB_OBJS += levenshtein.o
 LIB_OBJS += list-objects.o
 LIB_OBJS += ll-merge.o