Fix XNU / FreeBSD / OpenBSD / RHEL5 / NT bugs

For the first time ever, all tests in this codebase now pass, when
run automatically on macos, freebsd, openbsd, rhel5, rhel7, alpine
and windows via the network using the runit and runitd build tools

- Fix vfork exec path etc.
- Add XNU opendir() support
- Add OpenBSD opendir() support
- Add Linux history to syscalls.sh
- Use copy_file_range on FreeBSD 13+
- Fix system calls with 7+ arguments
- Fix Windows with greater than 16 FDs
- Fix RUNIT.COM and RUNITD.COM flakiness
- Fix OpenBSD munmap() when files are mapped
- Fix long double so it's actually long on Windows
- Fix OpenBSD truncate() and ftruncate() thunk typo
- Let Windows fcntl() be used on socket files descriptors
- Fix Windows fstat() which had an accidental printf statement
- Fix RHEL5 CLOCK_MONOTONIC by not aliasing to CLOCK_MONOTONIC_RAW

This is wonderful. I never could have dreamed it would be possible
to get it working so well on so many platforms with tiny binaries.

Fixes #31
Fixes #25
Fixes #14

libc/sysv/calls/__accept-sysv.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/macros.internal.inc"
-.scall __accept$sysv 0x001e0063201e002b globl hidden
+.scall __accept$sysv 0x001e021d201e002b globl hidden

libc/sysv/calls/__execve-sysv.s

@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall __execve$sysv 0x003b003b203b003b globl hidden

libc/sysv/calls/__fork-sysv.s

@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall __fork$sysv 0x0002000220020039 globl hidden

libc/sysv/calls/copy_file_range-sysv.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/macros.internal.inc"
-.scall copy_file_range$sysv 0xffffffffffff0146 globl hidden
+.scall copy_file_range$sysv 0xffff0239ffff0146 globl hidden

libc/sysv/calls/execve-sysv.s

@@ -1,2 +0,0 @@
-.include "o/libc/sysv/macros.internal.inc"
-.scall execve$sysv 0x003b003b203b003b globl hidden

libc/sysv/calls/fork-sysv.s

@@ -1,2 +0,0 @@
-.include "o/libc/sysv/macros.internal.inc"
-.scall fork$sysv 0x0002000220020039 globl hidden

libc/sysv/calls/getdents.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/macros.internal.inc"
-.scall getdents 0x00630110ffff00d9 globl hidden
+.scall getdents 0x0063011020c400d9 globl hidden

libc/sysv/calls/getdirentries.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/macros.internal.inc"
-.scall getdirentries 0xffff022a2158ffff globl
+.scall getdirentries 0xffff022a20c4ffff globl

libc/sysv/calls/ptrace-sysv.s

@@ -0,0 +1,2 @@
+.include "o/libc/sysv/macros.internal.inc"
+.scall ptrace$sysv 0x001a001a201a0065 globl hidden

libc/sysv/calls/ptrace.s

@@ -1,2 +0,0 @@
-.include "o/libc/sysv/macros.internal.inc"
-.scall ptrace 0x001a001a201a0065 globl

libc/sysv/calls/sysctl.s

@@ -1,2 +1,2 @@
 .include "o/libc/sysv/macros.internal.inc"
-.scall sysctl 0x00caffff20caffff globl
+.scall sysctl 0x00ca00ca20caffff globl