regex: Fix unicode othercasing
regex: Fix unicode othercasing

The old _pcre_ucp_othercase() function was wrong in returning
NOTACHAR (0xffffffff) for characters that aren't changed by upper-
and lower-casing. This led to PCRE internally using incorrect (or
at least inefficient) character classes when using G_REGEX_CASELESS.

E.g. [Z-\x{100}] turned into:

[Z\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{39c}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{fffe}\x{178}z-\x{101}]

instead of the expected and efficient

[Z\x{39c}\x{178}z-\x{101}]

https://bugzilla.gnome.org/show_bug.cgi?id=678273

pstglia/platform-external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,pstglia/external-bluetooth-glib,justinkb/aosp-bluez.glib,01org/android-bluez-glib,01org/android-bluez-glib,iConsole/Console-OS_external_bluetooth_glib,justinkb/aosp-bluez.glib,pstglia/external-bluetooth-glib,darren-clark/android_platform_external_bluetooth_glib,justinkb/aosp-bluez.glib,justinkb/aosp-bluez.glib,bluez-android/glib,bluez-android/glib,justinkb/aosp-bluez.glib,01org/android-bluez-glib,pstglia/platform-external-bluetooth-glib,01org/android-bluez-glib,pstglia/platform-external-bluetooth-glib,darren-clark/android_platform_external_bluetooth_glib,darren-clark/android_platform_external_bluetooth_glib,darren-clark/android_platform_external_bluetooth_glib,pstglia/platform-external-bluetooth-glib,pstglia/external-bluetooth-glib,01org/android-bluez-glib,bluez-android/glib,iConsole/Console-OS_external_bluetooth_glib,bluez-android/glib,bluez-android/glib,pstglia/external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,iConsole/Console-OS_external_bluetooth_glib,darren-clark/android_platform_external_bluetooth_glib,pstglia/platform-external-bluetooth-glib,pstglia/external-bluetooth-glib