provide PAGE_SIZE as a constant value of 8192 on or1k

according to Stefan Kristiansson, or1k page size is not actually
variable and the value of 8192 is part of the ABI.
add framework for mmap2 syscall unit to vary by arch
fix broken offset argument to the mmap2 syscall on or1k

for or1k, the kernel expects the offset passed to mmap2 in units of
the 8k page size, not the standard unit of 4k used on most other
archs.
limit visibility of ffs function declaration to _XOPEN_SOURCE

per the standard, ffs is XSI shaded, whereas the other functions in
this header are in the base.
implement ffsl and ffsll functions

per the resolution of Austin Group issue #617, these are accepted for
XSI option in POSIX future and thus I'm treating them as standard
functions.
harden locale name handling and prevent slashes in LC_MESSAGES

the code which loads locale files was already rejecting locale names
containing slashes. however, LC_MESSAGES records a locale name even if
libc does not have a matching locale file, so that gettext or
application code can use the recorded locale name for message
translations to languages that libc does not support. this recorded
name was not being checked for slashes, meaning that such code could
potentially be tricked into directory traversal.

in addition, since the value of a locale category is sometimes used as
a pathname component by callers, the improved code rejects any value
beginning with a dot. this prevents traversal to the parent directory
via "..", use of the top-level locale directory via ".", and also
avoids "hidden" directories as a side effect.

finally, overly long locale names are now rejected (treated as an
unrecognized name and thus as an alias for C.UTF-8) rather than being
truncated.
update COPYRIGHT file to reflect new contributors
update notice on broken gcc versions in INSTALL file
release 1.1.4