pcre: add options to enable UTF and UCP support

Allow to compile PCRE with UTF-8/16/32 support and with
support for Unicode properties.

[Peter: whitespace fix]
Signed-off-by: Sven Neumann <neumann@teufel.de>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>