Revert "[cmake] Simplify and move the var init outside of ARG_MODULE."
Revert "[cmake] Simplify and move the var init outside of ARG_MODULE."

This reverts commit 1ff208ce2f6f1556cc43532113e2c9f2348f9cba.
It causes duplicate cintdll targets and a race.

karies/root,olifre/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,karies/root,karies/root,karies/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,karies/root