diff --git a/src/lib/core/BUILD.gn b/src/lib/core/BUILD.gn
index 137c8f7537a065..8e02a327347b7c 100644
--- a/src/lib/core/BUILD.gn
+++ b/src/lib/core/BUILD.gn
@@ -20,6 +20,11 @@ import("${chip_root}/gn/chip/tests.gni")
 import("${chip_root}/src/inet/inet.gni")
 import("core.gni")
 
+declare_args() {
+  cflags_c_ext = []
+  cflags_cc_ext = []
+}
+
 buildconfig_header("chip_buildconfig") {
   header = "CHIPBuildConfig.h"
   header_dir = "core"
@@ -110,6 +115,9 @@ static_library("core") {
     "CHIPTLVWriter.cpp",
   ]
 
+  cflags_c = cflags_c_ext
+  cflags_cc = cflags_cc_ext
+
   public_deps = [
     ":chip_config_header",
     "${chip_root}/src/ble",