Merge branch 'rs/grep-expr-cleanup'

Code clean-up.

* rs/grep-expr-cleanup:
  grep: use grep_and_expr() in compile_pattern_and()
  grep: extract grep_binexp() from grep_or_expr()
  grep: use grep_not_expr() in compile_pattern_not()
  grep: use grep_or_expr() in compile_pattern_or()

diff --cc grep.c
Simple merge