diff --git a/deno.spec b/deno.spec
index 3e476cd..3a654bf 100644
--- a/deno.spec
+++ b/deno.spec
@@ -113,8 +113,8 @@ export V8_FROM_SOURCE=1
 export CLANG_BASE_PATH=%{_prefix}
 export CC=clang
 export CXX=clang++
-export CFLAGS="%{optflags}"
-export CXXFLAGS="%{optflags}"
+export CFLAGS="%{optflags} -Wno-unknown-warning-option"
+export CXXFLAGS="%{optflags} -Wno-unknown-warning-option"
 # https://www.chromium.org/developers/gn-build-configuration
 export GN_ARGS="clang_version=${CLANG_VERSION} use_lld=true enable_nacl = false blink_symbol_level = 0 v8_symbol_level = 0"
 %{cargo_build}