Consistently use -std=gnu99 for gcc as well as clang.

This matters for C files that are also built for Windows. Previously they'd
be compiled with -std=gnu99 for the host but [effectively] -std=gnu89 for
Windows.

Bug: http://b/32019064
Test: builds, and can build libcrypto_utils without a manual -std= line
Change-Id: I9c5cc7832220b5c3d6a007ff10d076e26fd8c75d

cc/compiler.go

@@ -233,6 +233,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 
 	if !ctx.noDefaultCompilerFlags() {
 		flags.GlobalFlags = append(flags.GlobalFlags, instructionSetFlags)
+		flags.ConlyFlags = append(flags.ConlyFlags, "${config.CommonGlobalConlyflags}")
 
 		if flags.Clang {
 			flags.AsFlags = append(flags.AsFlags, tc.ClangAsflags())
@@ -241,8 +242,6 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 				tc.ClangCflags(),
 				"${config.CommonClangGlobalCflags}",
 				fmt.Sprintf("${config.%sClangGlobalCflags}", hod))
-
-			flags.ConlyFlags = append(flags.ConlyFlags, "${config.ClangExtraConlyflags}")
 		} else {
 			flags.CppFlags = append(flags.CppFlags, "${config.CommonGlobalCppflags}")
 			flags.GlobalFlags = append(flags.GlobalFlags,

cc/config/clang.go

@@ -93,10 +93,6 @@ func init() {
 		"-Wno-expansion-to-defined",
 	}, " "))
 
-	pctx.StaticVariable("ClangExtraConlyflags", strings.Join([]string{
-		"-std=gnu99",
-	}, " "))
-
 	pctx.StaticVariable("ClangExtraCppflags", strings.Join([]string{
 		// Disable -Winconsistent-missing-override until we can clean up the existing
 		// codebase for it.

cc/config/global.go

@@ -37,6 +37,10 @@ var (
 		"-UDEBUG",
 	}
 
+	commonGlobalConlyflags = []string{
+		"-std=gnu99",
+	}
+
 	deviceGlobalCflags = []string{
 		"-fdiagnostics-color",
 
@@ -72,6 +76,7 @@ func init() {
 	}
 
 	pctx.StaticVariable("CommonGlobalCflags", strings.Join(commonGlobalCflags, " "))
+	pctx.StaticVariable("CommonGlobalConlyflags", strings.Join(commonGlobalConlyflags, " "))
 	pctx.StaticVariable("DeviceGlobalCflags", strings.Join(deviceGlobalCflags, " "))
 	pctx.StaticVariable("HostGlobalCflags", strings.Join(hostGlobalCflags, " "))
 	pctx.StaticVariable("NoOverrideGlobalCflags", strings.Join(noOverrideGlobalCflags, " "))

cc/makevars.go

@@ -113,7 +113,9 @@ func makeVarsToolchain(ctx android.MakeVarsContext, secondPrefix string,
 		toolchain.ToolchainCflags(),
 		productExtraCflags,
 	}, " "))
-	ctx.Strict(makePrefix+"GLOBAL_CONLYFLAGS", "")
+	ctx.Strict(makePrefix+"GLOBAL_CONLYFLAGS", strings.Join([]string{
+		"${config.CommonGlobalConlyflags}",
+	}, " "))
 	ctx.Strict(makePrefix+"GLOBAL_CPPFLAGS", strings.Join([]string{
 		"${config.CommonGlobalCppflags}",
 		toolchain.Cppflags(),
@@ -161,7 +163,6 @@ func makeVarsToolchain(ctx android.MakeVarsContext, secondPrefix string,
 			clangExtras,
 			productExtraCflags,
 		}, " "))
-		ctx.Strict(clangPrefix+"GLOBAL_CONLYFLAGS", "${config.ClangExtraConlyflags}")
 		ctx.Strict(clangPrefix+"GLOBAL_CPPFLAGS", strings.Join([]string{
 			"${config.CommonClangGlobalCppflags}",
 			toolchain.ClangCppflags(),