Support turning phony warnings into errors

These still default to warnings, but if a board decides to set
BOARD_BROKEN_PHONY_TARGETS := false, they'll turn into errors. More
likely I'll just be marking the broken targets as broken, then switching
the logic here to be like the dup rules warnings/errors.

Test: On a build with warnings, try <missing>, "false", and "true"
Change-Id: I041e1ff4618c4114ec43015b6c0ae1b49b36b6f8

ui/build/config.go

@@ -50,8 +50,10 @@ type configImpl struct {
 	targetDevice    string
 	targetDeviceDir string
 
-	pdkBuild       bool
-	brokenDupRules bool
+	pdkBuild bool
+
+	brokenDupRules     bool
+	brokenPhonyTargets bool
 
 	pathReplaced bool
 }
@@ -577,6 +579,14 @@ func (c *configImpl) BuildBrokenDupRules() bool {
 	return c.brokenDupRules
 }
 
+func (c *configImpl) SetBuildBrokenPhonyTargets(val bool) {
+	c.brokenPhonyTargets = val
+}
+
+func (c *configImpl) BuildBrokenPhonyTargets() bool {
+	return c.brokenPhonyTargets
+}
+
 func (c *configImpl) SetTargetDeviceDir(dir string) {
 	c.targetDeviceDir = dir
 }

ui/build/dumpvars.go

@@ -165,10 +165,12 @@ func runMakeProductConfig(ctx Context, config Config) {
 		// Whether --werror_overriding_commands will work
 		"BUILD_BROKEN_DUP_RULES",
 
+		// Used to turn on --werror_ options in Kati
+		"BUILD_BROKEN_PHONY_TARGETS",
+
 		// Not used, but useful to be in the soong.log
 		"BUILD_BROKEN_ANDROIDMK_EXPORTS",
 		"BUILD_BROKEN_DUP_COPY_HEADERS",
-		"BUILD_BROKEN_PHONY_TARGETS",
 	}, exportEnvVars...), BannerVars...)
 
 	make_vars, err := dumpMakeVars(ctx, config, config.Arguments(), allVars, true)
@@ -196,4 +198,5 @@ func runMakeProductConfig(ctx Context, config Config) {
 
 	config.SetPdkBuild(make_vars["TARGET_BUILD_PDK"] == "true")
 	config.SetBuildBrokenDupRules(make_vars["BUILD_BROKEN_DUP_RULES"] == "true")
+	config.SetBuildBrokenPhonyTargets(make_vars["BUILD_BROKEN_PHONY_TARGETS"] != "false")
 }

ui/build/kati.go

@@ -93,6 +93,10 @@ func runKati(ctx Context, config Config) {
 		args = append(args, "--werror_overriding_commands")
 	}
 
+	if !config.BuildBrokenPhonyTargets() {
+		args = append(args, "--werror_real_to_phony", "--werror_phony_looks_real")
+	}
+
 	if !config.Environment().IsFalse("KATI_EMULATE_FIND") {
 		args = append(args, "--use_find_emulator")
 	}