bp2build implementation for c_std

Test: mixed_droid in conjunction with topic changes
Change-Id: Ic673c1b269f5082b490b32057eb60f3b73eb0940

cc/compiler.go

@@ -304,11 +304,24 @@ func parseCppStd(cppStdPtr *string) string {
 	cppStd := String(cppStdPtr)
 	switch cppStd {
 	case "":
-		cppStd = config.CppStdVersion
+		return config.CppStdVersion
 	case "experimental":
-		cppStd = config.ExperimentalCppStdVersion
+		return config.ExperimentalCppStdVersion
+	default:
+		return cppStd
+	}
+}
+
+func parseCStd(cStdPtr *string) string {
+	cStd := String(cStdPtr)
+	switch cStd {
+	case "":
+		return config.CStdVersion
+	case "experimental":
+		return config.ExperimentalCStdVersion
+	default:
+		return cStd
 	}
-	return cppStd
 }
 
 // Create a Flags struct that collects the compile flags from global values,
@@ -479,13 +492,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags, deps
 
 	flags.Global.CommonFlags = append(flags.Global.CommonFlags, tc.ToolchainCflags())
 
-	cStd := config.CStdVersion
-	if String(compiler.Properties.C_std) == "experimental" {
-		cStd = config.ExperimentalCStdVersion
-	} else if String(compiler.Properties.C_std) != "" {
-		cStd = String(compiler.Properties.C_std)
-	}
-
+	cStd := parseCStd(compiler.Properties.C_std)
 	cppStd := parseCppStd(compiler.Properties.Cpp_std)
 
 	cStd, cppStd = maybeReplaceGnuToC(compiler.Properties.Gnu_extensions, cStd, cppStd)