WIP: Fixed uint_64_t type typo noted in 1613

(cherry picked from commit be51633a) uint64_t is misspelled in a few cmake script templates. This is a minor issue mentioned in graphviz/graphviz#1613 (closed). It is marked as WIP because new compiler warnings are thrown which may indicate some declarations or casts are inadvertently changed. Needs review to ensure that fixing the typo isn't introducing additional issues.