diff --git a/cc/cc.go b/cc/cc.go
index 98c328f..f64107b 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -355,6 +355,12 @@
 		flags.conlyFlags = clangFilterUnknownCflags(flags.conlyFlags)
 		flags.ldFlags = clangFilterUnknownCflags(flags.ldFlags)
 
+		flags.cFlags = append(flags.cFlags, "${clangExtraCflags}")
+		flags.conlyFlags = append(flags.conlyFlags, "${clangExtraConlyflags}")
+		if arch.HostOrDevice.Device() {
+			flags.cFlags = append(flags.cFlags, "${clangExtraTargetCflags}")
+		}
+
 		target := "-target " + toolchain.ClangTriple()
 		gccPrefix := "-B" + filepath.Join(toolchain.GccRoot(), toolchain.GccTriple(), "bin")