libc: implement glibc's glob_pattern_p

Currently, glob is implemented but glob_pattern_p is not. This function
can trivially be implemented with existing glob machinery, since all it
does is to tell whether or not the string contains special symbols. This
is basically the same logic as is_literal, but with inverted return value.

The value of the "quote" parameter should also be inverted, since the man
page states that when the quote parameter is *non*-zero, then backslashes
are ignored. is_literal ignores them when useesc is *zero*.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>