diff --git a/firefox.spec b/firefox.spec
index 73faccd..a640b62 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -1122,8 +1122,8 @@ echo "ac_add_options --with-google-location-service-api-keyfile=`pwd`/google-loc
 echo "ac_add_options --with-google-safebrowsing-api-keyfile=`pwd`/google-api-key" >> .mozconfig
 
 # May result in empty --with-libclang-path= in earlier versions.
-# So far this is needed only for c8s.
-%if 0%{?rhel} == 8 && %{rhel_minor_version} >= 10
+# So far this is needed only for c8s/c9s.
+%if (0%{?rhel} == 8 && %{rhel_minor_version} >= 10) || (0%{?rhel} == 9 && %{rhel_minor_version} >= 4)
 # Clang 17 upstream's detection fails, tell it where to look.
 echo "ac_add_options --with-libclang-path=`llvm-config --libdir`" >> .mozconfig
 %endif