Remove legacy NDK code.

Test: make checkbuild
Bug: None
Change-Id: Ib25e851b5ac25e918c5e20d79348c6d705bddeb2

cc/compiler.go

@@ -299,6 +299,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags, deps
 	}
 
 	if ctx.useSdk() {
+		// TODO: Switch to --sysroot.
 		// The NDK headers are installed to a common sysroot. While a more
 		// typical Soong approach would be to only make the headers for the
 		// library you're using available, we're trying to emulate the NDK
@@ -307,6 +308,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags, deps
 			"-isystem "+getCurrentIncludePath(ctx).String(),
 			"-isystem "+getCurrentIncludePath(ctx).Join(ctx, config.NDKTriple(tc)).String())
 
+		// TODO: Migrate to API suffixed triple?
 		// Traditionally this has come from android/api-level.h, but with the
 		// libc headers unified it must be set by the build system since we
 		// don't have per-API level copies of that header now.
@@ -316,14 +318,6 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags, deps
 		}
 		flags.GlobalFlags = append(flags.GlobalFlags,
 			"-D__ANDROID_API__="+version)
-
-		// Until the full NDK has been migrated to using ndk_headers, we still
-		// need to add the legacy sysroot includes to get the full set of
-		// headers.
-		legacyIncludes := fmt.Sprintf(
-			"prebuilts/ndk/current/platforms/android-%s/arch-%s/usr/include",
-			ctx.sdkVersion(), ctx.Arch().ArchType.String())
-		flags.SystemIncludeFlags = append(flags.SystemIncludeFlags, "-isystem "+legacyIncludes)
 	}
 
 	if ctx.useVndk() {