libc/pause: Enable pause_nocancel for arches without __NR_pause

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
nptl/allocatestack.c: Fix stack mprotect alignment for STACK_GROWS_UP

mprotect() expects the first argument to be aligned to a page boundary.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>