complete work on safe recursive interpreters, C<Perl->new()>
revisit extra implicit arg that provides curthread/curinterp context
+Configure
+ make configuring+building away from source directory work (VPATH et al)
+ _r support
+ cross-compilation configuring
+ mmap support
+
+Locales
+ locales across packages
+ decimal separator (3,1415927 is Europeanese for an approximation of pi)
+
+Regexen
+ POSIX [:foo:] character classes
+ ([=bar=] and [.zap.] would nice too but there's no API for them)
+ approximate matching
+
Reliable Signals
alternate runops() for signal despatch
figure out how to die() in delayed sighandler