otherwise we cannot support an application's desire to use
asynchronous cancellation within the callback function. this change
also slightly debloats pthread_create.c.

we take advantage of the fact that unless self->cancelpt is 1,
cancellation cannot happen. so just increment it by 2 to temporarily
block cancellation. this drops pthread_create.o well under 1k.

with datagram sockets, depending on fprintf not to flush the output
early was very fragile; the new version simply uses a small fixed-size
buffer. it could be updated to dynamic-allocate large buffers if
needed, but i can't envision any admin being happy about finding
64kb-long lines in their syslog...

per the standard, SIGPIPE is not generated for SOCK_DGRAM.

it actually appears the hacks to block SIGPIPE are probably not
necessary, and potentially harmful. if i can confirm this, i'll remove
them.

some of these definitions were just plain wrong, others based on
outdated ancient "non-64" versions of the kernel interface.

as much as possible has now been moved out of bits/*

these changes break abi (the old abi for these functions was wrong),
but since they were not working anyway it can hardly matter.

it should be noted that flock does not mix well with standard fcntl
locking, but nonetheless some applications will attempt to use flock
instead of fcntl if both exist. options to configure or small patches
may be needed. debian maintainers have plenty of experience with this
unfortunate situation...

RLIM_* is in the reserved namespace for this header

trash in the upper 32 bits was making the kernel sleep forever in
select on 64-bit systems.

this eliminates the ugly static buffer in programs that use ptsname_r.

after fork, we have a new process and the pid is equal to the tid of
the new main thread. there is no need to make two separate syscalls to
obtain the same number.

we can do this without violating the namespace now that they are
macros/inline functions rather than extern functions. the motivation
is that gcc was generating giant, slow, horrible code for the old
functions, and now generates a single byte-swapping instruction.

the basic idea is that the only things in alltypes.h should be types
that either vary from system to system (in practice, not just in
theoretical la-la land - this is the implementation so we choose what
constraints we want to impose on ports) or which are needed by
multiple system headers.

1. saved errno was not being restored, illegally clearing errno to 0.
2. no need to backup and save errno around free; it will not touch
except perhaps when the program has already invoked UB...

actually FLT_ROUNDS needs to expand to a static inline function that
obtains the current rounding mode and returns it, but that will be
added later with fenv.h stuff.