Re: git-prompt.sh incompatible with non-basic global grep.patternType

> This may fix it.  I think the root cause is that logic to smear
> "pattern type" into various broken-down fields in grep_opt for the
> short-hands like --basic-regexp option needs to leave "I am setting
> this short-hand" mark to allow the grep_commit_pattern_type() that
> is done as the final step of the set-up sequence before we call
> compile_grep_patterns() can take notice.  The calls currently made
> to grep_set_pattern_type_option() when we parse "--basic-regexp" and
> friends forgets to override the "source of truth" field and only
> updates the broken-down fields.
> 
> An alternative may be to update places that parse "--basic-regexp"
> and friends to just write to .pattern_type_option without calling
> grep_set_pattern_type_option(); that might be a cleaner, but I am
> not feeling well today so I won't be able to do a deeper analysis
> right now.