diff --git a/llhttp.spec b/llhttp.spec
index 3378162..682c7c1 100644
--- a/llhttp.spec
+++ b/llhttp.spec
@@ -124,6 +124,8 @@ sed -r -i 's@\b(DESTINATION[[:blank:]]+)lib($|/)@\1%{_libdir}\2@' \
 rm -rvf node_modules
 
 cd release
+%set_build_flags
+export CFLAGS="${CFLAGS} -DLLHTTP_STRICT_MODE=1"
 %cmake -DBUILD_SHARED_LIBS:BOOL=ON
 %cmake_build