unix: drop support for pre-1.12 direct syscalls on darwin

Go 1.12 and newer are using libSystem for syscalls on darwin.
Go 1.11 is the last release to use direct syscalls. It hasn't been
supported since the release of Go 1.13 in September 2019, so drop
support for direct syscalls.

Change-Id: I2baf6f3d1031de8e474dc770369a25147e5efe2a
Reviewed-on: https://go-review.googlesource.com/c/sys/+/250437
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Author: tklauser

unix/mkall.sh

@@ -73,26 +73,22 @@ aix_ppc64)
 darwin_386)
 	mkerrors="$mkerrors -m32"
 	mksyscall="go run mksyscall.go -l32"
-	mksysnum="go run mksysnum.go $(xcrun --show-sdk-path --sdk macosx)/usr/include/sys/syscall.h"
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
 	mkasm="go run mkasm_darwin.go"
 	;;
 darwin_amd64)
 	mkerrors="$mkerrors -m64"
-	mksysnum="go run mksysnum.go $(xcrun --show-sdk-path --sdk macosx)/usr/include/sys/syscall.h"
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
 	mkasm="go run mkasm_darwin.go"
 	;;
 darwin_arm)
 	mkerrors="$mkerrors"
 	mksyscall="go run mksyscall.go -l32"
-	mksysnum="go run mksysnum.go $(xcrun --show-sdk-path --sdk iphoneos)/usr/include/sys/syscall.h"
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
 	mkasm="go run mkasm_darwin.go"
 	;;
 darwin_arm64)
 	mkerrors="$mkerrors -m64"
-	mksysnum="go run mksysnum.go $(xcrun --show-sdk-path --sdk iphoneos)/usr/include/sys/syscall.h"
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs"
 	mkasm="go run mkasm_darwin.go"
 	;;
@@ -226,8 +222,6 @@ esac
 				# aix/ppc64 script generates files instead of writing to stdin.
 				echo "$mksyscall -tags $GOOS,$GOARCH $syscall_goos $GOOSARCH_in && gofmt -w zsyscall_$GOOSARCH.go && gofmt -w zsyscall_"$GOOSARCH"_gccgo.go && gofmt -w zsyscall_"$GOOSARCH"_gc.go " ;
 			elif [ "$GOOS" == "darwin" ]; then
-			        # pre-1.12, direct syscalls
-			        echo "$mksyscall -tags $GOOS,$GOARCH,!go1.12 $syscall_goos syscall_darwin_${GOARCH}.1_11.go $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.1_11.go";
 			        # 1.12 and later, syscalls via libSystem
 				echo "$mksyscall -tags $GOOS,$GOARCH,go1.12 $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go";
 				# 1.13 and later, syscalls via libSystem (including syscallPtr)

unix/syscall_darwin_386.1_11.go

@@ -44,10 +44,6 @@ func (cmsg *Cmsghdr) SetLen(length int) {
 
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
-// SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions
-// of darwin/386 the syscall is called sysctl instead of __sysctl.
-const SYS___SYSCTL = SYS_SYSCTL
-
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
 //sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sys	Fstatfs(fd int, stat *Statfs_t) (err error) = SYS_FSTATFS64

unix/syscall_darwin_386.go

@@ -44,10 +44,6 @@ func (cmsg *Cmsghdr) SetLen(length int) {
 
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
-// SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions
-// of darwin/amd64 the syscall is called sysctl instead of __sysctl.
-const SYS___SYSCTL = SYS_SYSCTL
-
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
 //sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
 //sys	Fstatfs(fd int, stat *Statfs_t) (err error) = SYS_FSTATFS64

unix/syscall_darwin_amd64.1_11.go

@@ -44,10 +44,6 @@ func (cmsg *Cmsghdr) SetLen(length int) {
 
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno) // sic
 
-// SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions
-// of darwin/arm the syscall is called sysctl instead of __sysctl.
-const SYS___SYSCTL = SYS_SYSCTL
-
 //sys	Fstat(fd int, stat *Stat_t) (err error)
 //sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error)
 //sys	Fstatfs(fd int, stat *Statfs_t) (err error)

unix/syscall_darwin_amd64.go

@@ -46,10 +46,6 @@ func (cmsg *Cmsghdr) SetLen(length int) {
 
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno) // sic
 
-// SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions
-// of darwin/arm64 the syscall is called sysctl instead of __sysctl.
-const SYS___SYSCTL = SYS_SYSCTL
-
 //sys	Fstat(fd int, stat *Stat_t) (err error)
 //sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error)
 //sys	Fstatfs(fd int, stat *Statfs_t) (err error)