visibility primitives.
o Implement _tolower() and _toupper() POSIX.1-2001 (XSI) macros in
<ctype.h>.
o Reduce pollution in <runetype.h> by removing typedefs and using
implementation namespaced types.
o Add a typedef in <rune.h> to compensate for <runetype.h> losing its
typedefs.
Reviewed by: bde
# This appears to not break X11, but I'm having problems compiling the
# glide part of the server with or without this patch, so I can't tell
# for sure.
