unix: reverse default for 1.11/1.12 split

Make 1.11 the explicitly named case, and 1.12 the default.

Change-Id: Ic3674860eb9e8a5bb1cf1da12c5ac583cc0b0633
Reviewed-on: https://go-review.googlesource.com/c/155397
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/darwin_test.go

@@ -69,7 +69,7 @@ func init() {
 	}
 }
 
-// All the _trampoline functions in zsyscall_darwin_$ARCH.1_12.s
+// All the _trampoline functions in zsyscall_darwin_$ARCH.s
 var darwinTests = [...]darwinTest{
 	{"getgroups", libc_getgroups_trampoline},
 	{"setgroups", libc_setgroups_trampoline},

unix/mkall.sh

@@ -199,9 +199,9 @@ esac
 				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 $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go";
+			        echo "$mksyscall -tags $GOOS,$GOARCH,!go1.12 $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$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.1_12.go";
+				echo "$mksyscall -tags $GOOS,$GOARCH,go1.12 $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go";
 			else
 				echo "$mksyscall -tags $GOOS,$GOARCH $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go";
 			fi

unix/mkasm_darwin.go

@@ -27,9 +27,9 @@ func main() {
 	if err != nil {
 		log.Fatalf("can't open syscall_darwin_%s.go: %s", arch, err)
 	}
-	in3, err := ioutil.ReadFile(fmt.Sprintf("zsyscall_darwin_%s.1_12.go", arch))
+	in3, err := ioutil.ReadFile(fmt.Sprintf("zsyscall_darwin_%s.go", arch))
 	if err != nil {
-		log.Fatalf("can't open zsyscall_darwin_%s.1_12.go: %s", arch, err)
+		log.Fatalf("can't open zsyscall_darwin_%s.go: %s", arch, err)
 	}
 	in := string(in1) + string(in2) + string(in3)