cmd/release: set the minimum macOS version supported by Go 1.13

Set the minmacos version depending on the version of go being packaged
for macOS releases. Removed support for Go 1.12 since it is no longer
supported.

Fixes golang/go#36846
Updates golang/go#35459

Change-Id: Ifb9a0296fde5ed87da72d7719a714744484cc7db
Reviewed-on: https://go-review.googlesource.com/c/build/+/221100
Run-TryBot: Carlos Amedee <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Alexander Rakoczy <[email protected]>

cmd/release/release.go

@@ -332,8 +332,7 @@ func (b *Build) make() error {
 	}
 
 	// Issues #36025 #35459
-	// TODO (amedee): remove check for go1.14 once #36845 and #36846 are resolved.
-	if b.OS == "darwin" && b.Arch == "amd64" && strings.HasPrefix(*version, "go1.14") {
+	if b.OS == "darwin" && b.Arch == "amd64" {
 		minMacVersion := minSupportedMacOSVersion(*version)
 		env = append(env, fmt.Sprintf("CGO_CFLAGS=-mmacosx-version-min=%s", minMacVersion))
 	}
@@ -886,22 +885,17 @@ func setGOARCH(env []string, goarch string) []string {
 }
 
 // minSupportedMacOSVersion provides the minimum supported macOS
-// version (of the form N.M) for each version of Go >= go1.12.
+// version (of the form N.M) for supported Go versions.
 func minSupportedMacOSVersion(goVer string) string {
 	// TODO(amedee): Use a version package to compare versions of Go.
 
 	// The minimum supported version of macOS with each version of go:
-	// go1.12 - macOS 10.10
 	// go1.13 - macOS 10.11
 	// go1.14 - macOS 10.11
 	// go1.15 - macOS 10.12
-	minMacVersion := "10.11"
-	if strings.HasPrefix(goVer, "go1.12.") {
-		minMacVersion = "10.10"
-		return minMacVersion
-	}
-	if strings.HasPrefix(goVer, "go1.15") {
-		minMacVersion = "10.12"
+	minMacVersion := "10.12"
+	if strings.HasPrefix(goVer, "go1.13") || strings.HasPrefix(goVer, "go1.14") {
+		minMacVersion = "10.11"
 		return minMacVersion
 	}
 	return minMacVersion

cmd/release/release_test.go

@@ -25,7 +25,6 @@ func TestMinSupportedMacOSVersion(t *testing.T) {
 		goVer     string
 		wantMacOS string
 	}{
-		{"patch_release_12", "go1.12.1", "10.10"},
 		{"minor_release_13", "go1.13", "10.11"},
 		{"minor_release_14", "go1.14", "10.11"},
 		{"rc_release_13", "go1.13rc1", "10.11"},