Add TARGET_BUILD_UNBUNDLED as a variable to control builds.

Test: m droid
Test: TH, in particular builds green on ub-launcher3-master
Bug: 157549171
Change-Id: Ifc5b2759c10672e4b253ddd208b02e5af17e8dad

ui/build/config.go

@@ -592,6 +592,7 @@ func (c *configImpl) Lunch(ctx Context, product, variant string) {
 	c.environ.Set("TARGET_BUILD_VARIANT", variant)
 	c.environ.Set("TARGET_BUILD_TYPE", "release")
 	c.environ.Unset("TARGET_BUILD_APPS")
+	c.environ.Unset("TARGET_BUILD_UNBUNDLED")
 }
 
 // Tapas configures the environment to build one or more unbundled apps,

ui/build/dumpvars.go

@@ -142,6 +142,7 @@ var BannerVars = []string{
 	"TARGET_BUILD_VARIANT",
 	"TARGET_BUILD_TYPE",
 	"TARGET_BUILD_APPS",
+	"TARGET_BUILD_UNBUNDLED",
 	"TARGET_ARCH",
 	"TARGET_ARCH_VARIANT",
 	"TARGET_CPU_VARIANT",
@@ -186,6 +187,7 @@ func runMakeProductConfig(ctx Context, config Config) {
 		"TARGET_PRODUCT",
 		"TARGET_BUILD_VARIANT",
 		"TARGET_BUILD_APPS",
+		"TARGET_BUILD_UNBUNDLED",
 
 		// compiler wrappers set up by make
 		"CC_WRAPPER",