to work similarly to Unicode tech reports and Java
notation \uXXXX (and already existing \x{XXXX))?
more than four hexdigits? make also \U+XXXX work?
+ overloadable regex assertions? e.g. in Thai \b cannot
+ be deduced by any simple character class boundary rules,
+ word boundaries must algorithmically computed
see ext/Encode/Todo for notes and references about proper detection
of malformed UTF-8
turn Cwd into an XS module? (Configure already probes for getcwd())
mmap for speeding up input? (Configure already probes for the mmap family)
sendmsg, recvmsg? (Configure doesn't probe for these but the units exist)
+ sockatmark?
setitimer, getitimer? (the metaconfig units exist)
Ongoing