Convert yacc to a single RuleBuilder rule

So that <module>/gen/yacc/... is (re)created by a single rule, previous
files are removed, and location.hh is in the build graph when it is
produced.

Test: treehugger
Change-Id: I2f6e47ea07f315e10ae1cb8ad50697e7123d0285

cc/util.go

@@ -67,7 +67,6 @@ func flagsToBuilderFlags(in Flags) builderFlags {
 		toolingCppFlags: strings.Join(in.ToolingCppFlags, " "),
 		conlyFlags:      strings.Join(in.ConlyFlags, " "),
 		cppFlags:        strings.Join(in.CppFlags, " "),
-		yaccFlags:       strings.Join(in.YaccFlags, " "),
 		aidlFlags:       strings.Join(in.aidlFlags, " "),
 		rsFlags:         strings.Join(in.rsFlags, " "),
 		ldFlags:         strings.Join(in.LdFlags, " "),
@@ -87,6 +86,8 @@ func flagsToBuilderFlags(in Flags) builderFlags {
 		proto:            in.proto,
 		protoC:           in.protoC,
 		protoOptionsFile: in.protoOptionsFile,
+
+		yacc: in.Yacc,
 	}
 }