vendor: update buildkit with typed errors support

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/golang.org/x/sys/unix/syscall_unix.go

@@ -12,6 +12,8 @@ import (
 	"sync"
 	"syscall"
 	"unsafe"
+
+	"golang.org/x/sys/internal/unsafeheader"
 )
 
 var (
@@ -76,7 +78,7 @@ func SignalName(s syscall.Signal) string {
 // The signal name should start with "SIG".
 func SignalNum(s string) syscall.Signal {
 	signalNameMapOnce.Do(func() {
-		signalNameMap = make(map[string]syscall.Signal)
+		signalNameMap = make(map[string]syscall.Signal, len(signalList))
 		for _, signal := range signalList {
 			signalNameMap[signal.name] = signal.num
 		}
@@ -113,15 +115,12 @@ func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (d
 		return nil, errno
 	}
 
-	// Slice memory layout
-	var sl = struct {
-		addr uintptr
-		len  int
-		cap  int
-	}{addr, length, length}
-
-	// Use unsafe to turn sl into a []byte.
-	b := *(*[]byte)(unsafe.Pointer(&sl))
+	// Use unsafe to convert addr into a []byte.
+	var b []byte
+	hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b))
+	hdr.Data = unsafe.Pointer(addr)
+	hdr.Cap = length
+	hdr.Len = length
 
 	// Register mapping in m and return it.
 	p := &b[cap(b)-1]