diff --git a/toolchain/toolchain-external/pkg-toolchain-external.mk b/toolchain/toolchain-external/pkg-toolchain-external.mk
index df0b686772..3e5236bee5 100644
--- a/toolchain/toolchain-external/pkg-toolchain-external.mk
+++ b/toolchain/toolchain-external/pkg-toolchain-external.mk
@@ -531,7 +531,7 @@ define $(2)_CONFIGURE_CMDS
 	$$(Q)$$(call check_unusable_toolchain,$$(TOOLCHAIN_EXTERNAL_CC))
 	$$(Q)SYSROOT_DIR="$$(call toolchain_find_sysroot,$$(TOOLCHAIN_EXTERNAL_CC))" ; \
 	$$(call check_kernel_headers_version,\
-		$$(BUILD_DIR)\
+		$$(BUILD_DIR),\
 		$$(call toolchain_find_sysroot,$$(TOOLCHAIN_EXTERNAL_CC)),\
 		$$(call qstrip,$$(BR2_TOOLCHAIN_HEADERS_AT_LEAST))); \
 	$$(call check_gcc_version,$$(TOOLCHAIN_EXTERNAL_CC),\