diff --git a/app/darwin_amd64.go b/app/darwin_desktop.go
similarity index 100%
rename from app/darwin_amd64.go
rename to app/darwin_desktop.go
diff --git a/app/darwin_amd64.m b/app/darwin_desktop.m
similarity index 100%
rename from app/darwin_amd64.m
rename to app/darwin_desktop.m
diff --git a/app/darwin_armx.go b/app/darwin_ios.go
similarity index 100%
rename from app/darwin_armx.go
rename to app/darwin_ios.go
diff --git a/app/darwin_armx.m b/app/darwin_ios.m
similarity index 100%
rename from app/darwin_armx.m
rename to app/darwin_ios.m
diff --git a/cmd/gomobile/bind.go b/cmd/gomobile/bind.go
index e5e1e57..adbf66e 100644
--- a/cmd/gomobile/bind.go
+++ b/cmd/gomobile/bind.go
@@ -133,8 +133,7 @@
 		if !xcodeAvailable() {
 			return fmt.Errorf("-target=ios requires XCode")
 		}
-		// TODO: use targetArchs?
-		return goIOSBind(gobind, pkgs)
+		return goIOSBind(gobind, pkgs, targetArchs)
 	default:
 		return fmt.Errorf(`invalid -target=%q`, buildTarget)
 	}
diff --git a/cmd/gomobile/bind_iosapp.go b/cmd/gomobile/bind_iosapp.go
index c7f327a..6d95def 100644
--- a/cmd/gomobile/bind_iosapp.go
+++ b/cmd/gomobile/bind_iosapp.go
@@ -15,7 +15,7 @@
 	"text/template"
 )
 
-func goIOSBind(gobind string, pkgs []*build.Package) error {
+func goIOSBind(gobind string, pkgs []*build.Package, archs []string) error {
 	// Run gobind to generate the bindings
 	cmd := exec.Command(
 		gobind,
@@ -56,14 +56,14 @@
 
 	cmd = exec.Command("xcrun", "lipo", "-create")
 
-	for _, env := range [][]string{darwinArmEnv, darwinArm64Env, darwinAmd64Env} {
+	for _, arch := range archs {
+		env := darwinEnv[arch]
 		env = append(env, gopath)
-		arch := archClang(getenv(env, "GOARCH"))
 		path, err := goIOSBindArchive(name, env)
 		if err != nil {
 			return fmt.Errorf("darwin-%s: %v", arch, err)
 		}
-		cmd.Args = append(cmd.Args, "-arch", arch, path)
+		cmd.Args = append(cmd.Args, "-arch", archClang(arch), path)
 	}
 
 	// Build static framework output directory.
diff --git a/cmd/gomobile/build.go b/cmd/gomobile/build.go
index 6ee55f2..bdd3fe0 100644
--- a/cmd/gomobile/build.go
+++ b/cmd/gomobile/build.go
@@ -111,17 +111,19 @@
 			return err
 		}
 	case "darwin":
-		// TODO: use targetArchs?
 		if !xcodeAvailable() {
 			return fmt.Errorf("-target=ios requires XCode")
 		}
 		if pkg.Name != "main" {
-			if err := goBuild(pkg.ImportPath, darwinArmEnv); err != nil {
-				return err
+			for _, arch := range targetArchs {
+				env := darwinEnv[arch]
+				if err := goBuild(pkg.ImportPath, env); err != nil {
+					return err
+				}
 			}
-			return goBuild(pkg.ImportPath, darwinArm64Env)
+			return nil
 		}
-		nmpkgs, err = goIOSBuild(pkg, buildBundleID)
+		nmpkgs, err = goIOSBuild(pkg, buildBundleID, targetArchs)
 		if err != nil {
 			return err
 		}
@@ -329,16 +331,8 @@
 	}
 
 	// verify all archs are supported one while deduping.
-	var supported []string
-	switch os {
-	case "ios":
-		supported = []string{"arm", "arm64", "amd64"}
-	case "android":
-		supported = []string{"arm", "arm64", "386", "amd64"}
-	}
-
 	isSupported := func(arch string) bool {
-		for _, a := range supported {
+		for _, a := range allArchs {
 			if a == arch {
 				return true
 			}
@@ -364,7 +358,7 @@
 		targetOS = "darwin"
 	}
 	if all {
-		return targetOS, supported, nil
+		return targetOS, allArchs, nil
 	}
 	return targetOS, archs, nil
 }
diff --git a/cmd/gomobile/build_darwin_test.go b/cmd/gomobile/build_darwin_test.go
index d375a7a..3434952 100644
--- a/cmd/gomobile/build_darwin_test.go
+++ b/cmd/gomobile/build_darwin_test.go
@@ -76,7 +76,7 @@
 echo "{{template "infoplist" .Xinfo}}" > $WORK/main/Info.plist
 mkdir -p $WORK/main/Images.xcassets/AppIcon.appiconset
 echo "{{.Xcontents}}" > $WORK/main/Images.xcassets/AppIcon.appiconset/Contents.json
-GOOS=darwin GOARCH=arm GOARM=7 CC=clang-iphoneos CXX=clang-iphoneos CGO_CFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch armv7 CGO_LDFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch armv7 CGO_ENABLED=1 go build -tags tag1 ios -x -o=$WORK/arm golang.org/x/mobile/example/basic
+GOARM=7 GOOS=darwin GOARCH=arm CC=clang-iphoneos CXX=clang-iphoneos CGO_CFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch armv7 CGO_LDFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch armv7 CGO_ENABLED=1 go build -tags tag1 ios -x -o=$WORK/arm golang.org/x/mobile/example/basic
 GOOS=darwin GOARCH=arm64 CC=clang-iphoneos CXX=clang-iphoneos CGO_CFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch arm64 CGO_LDFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch arm64 CGO_ENABLED=1 go build -tags tag1 ios -x -o=$WORK/arm64 golang.org/x/mobile/example/basic
 xcrun lipo -create $WORK/arm $WORK/arm64 -o $WORK/main/main
 mkdir -p $WORK/main/assets
diff --git a/cmd/gomobile/build_iosapp.go b/cmd/gomobile/build_iosapp.go
index 3146173..67455f9 100644
--- a/cmd/gomobile/build_iosapp.go
+++ b/cmd/gomobile/build_iosapp.go
@@ -19,7 +19,7 @@
 	"text/template"
 )
 
-func goIOSBuild(pkg *build.Package, bundleID string) (map[string]bool, error) {
+func goIOSBuild(pkg *build.Package, bundleID string, archs []string) (map[string]bool, error) {
 	src := pkg.ImportPath
 	if buildO != "" && !strings.HasSuffix(buildO, ".app") {
 		return nil, fmt.Errorf("-o must have an .app for -target=ios")
@@ -64,29 +64,28 @@
 
 	ctx.BuildTags = append(ctx.BuildTags, "ios")
 
-	armPath := filepath.Join(tmpdir, "arm")
-	if err := goBuild(src, darwinArmEnv, "-o="+armPath); err != nil {
-		return nil, err
-	}
-	nmpkgs, err := extractPkgs(darwinArmNM, armPath)
-	if err != nil {
-		return nil, err
-	}
-
-	arm64Path := filepath.Join(tmpdir, "arm64")
-	if err := goBuild(src, darwinArm64Env, "-o="+arm64Path); err != nil {
-		return nil, err
-	}
-
-	// Apple requires builds to target both darwin/arm and darwin/arm64.
 	// We are using lipo tool to build multiarchitecture binaries.
-	// TODO(jbd): Investigate the new announcements about iO9's fat binary
-	// size limitations are breaking this feature.
 	cmd := exec.Command(
 		"xcrun", "lipo",
-		"-create", armPath, arm64Path,
 		"-o", filepath.Join(tmpdir, "main/main"),
+		"-create",
 	)
+	var nmpkgs map[string]bool
+	for _, arch := range archs {
+		path := filepath.Join(tmpdir, arch)
+		if err := goBuild(src, darwinEnv[arch], "-o="+path); err != nil {
+			return nil, err
+		}
+		if nmpkgs == nil {
+			var err error
+			nmpkgs, err = extractPkgs(darwinArmNM, path)
+			if err != nil {
+				return nil, err
+			}
+		}
+		cmd.Args = append(cmd.Args, path)
+	}
+
 	if err := runCmd(cmd); err != nil {
 		return nil, err
 	}
diff --git a/cmd/gomobile/build_test.go b/cmd/gomobile/build_test.go
index f353f7b..eb6ef58 100644
--- a/cmd/gomobile/build_test.go
+++ b/cmd/gomobile/build_test.go
@@ -109,8 +109,7 @@
 `))
 
 func TestParseBuildTargetFlag(t *testing.T) {
-	androidArchs := "arm,arm64,386,amd64"
-	iosArchs := "arm,arm64,amd64"
+	archs := strings.Join(allArchs, ",")
 
 	tests := []struct {
 		in        string
@@ -118,12 +117,12 @@
 		wantOS    string
 		wantArchs string
 	}{
-		{"android", false, "android", androidArchs},
-		{"android,android/arm", false, "android", androidArchs},
+		{"android", false, "android", archs},
+		{"android,android/arm", false, "android", archs},
 		{"android/arm", false, "android", "arm"},
 
-		{"ios", false, "darwin", iosArchs},
-		{"ios,ios/arm", false, "darwin", iosArchs},
+		{"ios", false, "darwin", archs},
+		{"ios,ios/arm", false, "darwin", archs},
 		{"ios/arm", false, "darwin", "arm"},
 		{"ios/amd64", false, "darwin", "amd64"},
 
diff --git a/cmd/gomobile/env.go b/cmd/gomobile/env.go
index 45bd9a1..8714dbb 100644
--- a/cmd/gomobile/env.go
+++ b/cmd/gomobile/env.go
@@ -18,15 +18,12 @@
 
 	androidEnv map[string][]string // android arch -> []string
 
-	darwinArmEnv   []string
-	darwinArm64Env []string
-	darwin386Env   []string
-	darwinAmd64Env []string
+	darwinEnv map[string][]string
 
 	androidArmNM string
 	darwinArmNM  string
 
-	archs = []string{"arm", "arm64", "386", "amd64"}
+	allArchs = []string{"arm", "arm64", "386", "amd64"}
 )
 
 func buildEnvInit() (cleanup func(), err error) {
@@ -104,52 +101,38 @@
 		return nil
 	}
 
-	clang, cflags, err := envClang("iphoneos")
-	if err != nil {
-		return err
-	}
-	darwinArmEnv = []string{
-		"GOOS=darwin",
-		"GOARCH=arm",
-		"GOARM=7",
-		"CC=" + clang,
-		"CXX=" + clang,
-		"CGO_CFLAGS=" + cflags + " -miphoneos-version-min=6.1 -arch " + archClang("arm"),
-		"CGO_LDFLAGS=" + cflags + " -miphoneos-version-min=6.1 -arch " + archClang("arm"),
-		"CGO_ENABLED=1",
-	}
 	darwinArmNM = "nm"
-	darwinArm64Env = []string{
-		"GOOS=darwin",
-		"GOARCH=arm64",
-		"CC=" + clang,
-		"CXX=" + clang,
-		"CGO_CFLAGS=" + cflags + " -miphoneos-version-min=6.1 -arch " + archClang("arm64"),
-		"CGO_LDFLAGS=" + cflags + " -miphoneos-version-min=6.1 -arch " + archClang("arm64"),
-		"CGO_ENABLED=1",
-	}
-
-	clang, cflags, err = envClang("iphonesimulator")
-	if err != nil {
-		return err
-	}
-	darwin386Env = []string{
-		"GOOS=darwin",
-		"GOARCH=386",
-		"CC=" + clang,
-		"CXX=" + clang,
-		"CGO_CFLAGS=" + cflags + " -mios-simulator-version-min=6.1 -arch " + archClang("386"),
-		"CGO_LDFLAGS=" + cflags + " -mios-simulator-version-min=6.1 -arch " + archClang("386"),
-		"CGO_ENABLED=1",
-	}
-	darwinAmd64Env = []string{
-		"GOOS=darwin",
-		"GOARCH=amd64",
-		"CC=" + clang,
-		"CXX=" + clang,
-		"CGO_CFLAGS=" + cflags + " -mios-simulator-version-min=6.1 -arch x86_64",
-		"CGO_LDFLAGS=" + cflags + " -mios-simulator-version-min=6.1 -arch x86_64",
-		"CGO_ENABLED=1",
+	darwinEnv = make(map[string][]string)
+	for _, arch := range allArchs {
+		var env []string
+		var err error
+		var clang, cflags string
+		switch arch {
+		case "arm":
+			env = append(env, "GOARM=7")
+			fallthrough
+		case "arm64":
+			clang, cflags, err = envClang("iphoneos")
+			cflags += " -miphoneos-version-min=6.1"
+		case "386", "amd64":
+			clang, cflags, err = envClang("iphonesimulator")
+			cflags += " -mios-simulator-version-min=6.1"
+		default:
+			panic(fmt.Errorf("unknown GOARCH: %q", arch))
+		}
+		if err != nil {
+			return err
+		}
+		env = append(env,
+			"GOOS=darwin",
+			"GOARCH="+arch,
+			"CC="+clang,
+			"CXX="+clang,
+			"CGO_CFLAGS="+cflags+" -arch "+archClang(arch),
+			"CGO_LDFLAGS="+cflags+" -arch "+archClang(arch),
+			"CGO_ENABLED=1",
+		)
+		darwinEnv[arch] = env
 	}
 
 	return nil
@@ -181,7 +164,6 @@
 		return "", "", fmt.Errorf("xcrun --show-sdk-path: %v\n%s", err, out)
 	}
 	sdk := strings.TrimSpace(string(out))
-
 	return clang, "-isysroot " + sdk, nil
 }
 
diff --git a/cmd/gomobile/init.go b/cmd/gomobile/init.go
index 10e7370..fba9308 100644
--- a/cmd/gomobile/init.go
+++ b/cmd/gomobile/init.go
@@ -151,7 +151,7 @@
 	}
 	toolsDir := filepath.Join(initNDK, "prebuilt", archNDK(), "bin")
 	py27 := filepath.Join(toolsDir, "python2.7")
-	for _, arch := range archs {
+	for _, arch := range allArchs {
 		t := ndk[arch]
 		// Split android-XX to get the api version.
 		platform := strings.SplitN(t.platform, "-", 2)
@@ -226,7 +226,7 @@
 		}
 	}
 
-	for _, arch := range archs {
+	for _, arch := range allArchs {
 		t := ndk[arch]
 		abi := t.arch
 		if abi == "arm" {
diff --git a/exp/gl/glutil/context_darwin_amd64.go b/exp/gl/glutil/context_darwin_desktop.go
similarity index 100%
rename from exp/gl/glutil/context_darwin_amd64.go
rename to exp/gl/glutil/context_darwin_desktop.go