internal/rosa: patch header search paths

This removes the need for reference CFLAGS in the standard toolchain.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/go.go

@@ -31,7 +31,7 @@ rm \
 	syscall/creds_test.go \
 	net/multicast_test.go
 
-CC="${CC} ${LDFLAGS}" ./all.bash
+CC="cc -Qunused-arguments ${LDFLAGS}" ./all.bash
 `, pkg.Path(AbsUsrSrc.Append("go1.4-bootstrap"), false, pkg.NewHTTPGetTar(
 		nil, "https://dl.google.com/go/go1.4-bootstrap-20171003.tar.gz",
 		mustDecode(checksum),
@@ -48,6 +48,7 @@ func (t Toolchain) newGo(
 	return t.New("go"+version, []pkg.Artifact{
 		boot,
 	}, nil, slices.Concat([]string{
+		"CC=cc",
 		"GOCACHE=/tmp/gocache",
 		"GOROOT_BOOTSTRAP=/system/go",
 		"CGO_" + ldflags(false) + " -O2 -g",