diff --git a/makefiles/vars.inc.mk b/makefiles/vars.inc.mk
index e27e5797fc..cbec3d58dc 100644
--- a/makefiles/vars.inc.mk
+++ b/makefiles/vars.inc.mk
@@ -47,6 +47,7 @@ export CC                    # The C compiler to use.
 export CXX                   # The CXX compiler to use.
 export CCAS                  # The C compiler to use for assembler files, typically the same as CC.
 export CFLAGS                # The compiler flags. Must only ever be used with `+=`.
+export CFLAGS_CPU            # CPU architecture specific compiler flags
 export CXXUWFLAGS            # (Patterns of) flags in CFLAGS that should not be passed to CXX.
 export CXXEXFLAGS            # Additional flags that should be passed to CXX.
 export CCASUWFLAGS           # (Patterns of) flags in CFLAGS that should not be passed to CCAS.