Replace syscall::pipe2 with pipe scheme.

See merge request redox-os/relibc!410

epoll: check for zero or negative size argument

See merge request redox-os/relibc!409

Fix misaligned stack pointer on aarch64

See merge request redox-os/relibc!408

change winsize to struct winsize

See merge request redox-os/relibc!406

strtof(), strtod(): handle NaN and Infinity

See merge request redox-os/relibc!405

Adding tcsetwinsize

See merge request redox-os/relibc!404

Fix warnings

See merge request redox-os/relibc!349

system(): on command == NULL, return nonzero if shell exists

See merge request redox-os/relibc!403

Adding some wcst* functions

See merge request !400

Rustfmt

See merge request redox-os/relibc!398

lockf implementation proposal

See merge request redox-os/relibc!396

Fix sem_t definition and allow nullable pthread destructors

See merge request redox-os/relibc!395