9. Case-insensitive matching applies only to characters whose values
are less than 128, unless PCRE is built with Unicode property support.
Even when Unicode property support is available, PCRE still uses its
own character tables when checking the case of low-valued characters,
so as not to degrade performance. The Unicode property information is
used only for characters with higher values. Even when Unicode property
support is available, PCRE supports case-insensitive matching only when
there is a one-to-one mapping between a letter's cases. There are a
small number of many-to-one mappings in Unicode; these are not sup-
ported by PCRE.
I suspect Khaleds compiles PCRE with --enable-utf8 and not with --enable-unicode-properties. The latter includes a 30k mapping of lower and uppercasing in UTF-8. Should add a bug/feature request when i get home.