Improve system calls

- Wrap clock_getres()
- Wrap sched_setscheduler()
- Make sleep() api conformant
- Polyfill sleep() using select()
- Improve clock_gettime() polyfill
- Make nanosleep() POSIX conformant
- Slightly improve some DNS functions
- Further strengthen pledge() sandboxing
- Improve rounding of timeval / timespec
- Allow layering of pledge() calls on Linux
- Polyfill sched_yield() using select() on XNU
- Delete more system constants we probably don't need

libc/intrin/intrin.mk

@@ -145,10 +145,7 @@ o/$(MODE)/libc/intrin/createfilemapping.o		\
 o/$(MODE)/libc/intrin/createfilemappingnuma.o		\
 o/$(MODE)/libc/intrin/waitformultipleobjects.o		\
 o/$(MODE)/libc/intrin/generateconsolectrlevent.o	\
-o/$(MODE)/libc/intrin/wsawaitformultipleevents.o	\
-o/$(MODE)/libc/intrin/kstarttsc.o			\
-o/$(MODE)/libc/intrin/nomultics.o			\
-o/$(MODE)/libc/intrin/ntconsolemode.o:			\
+o/$(MODE)/libc/intrin/wsawaitformultipleevents.o:	\
 		OVERRIDE_CFLAGS +=			\
 			-Os				\
 			-fwrapv				\