Fix the name of the CMake variable in the README
Fix the name of the CMake variable in the README


Former-commit-id: 28f26191437b500c08182a75d5d5a5e685b4f4c2
rbaghdadi/pencil-benchmark,pencil-language/pencil-benchmark,rbaghdadi/pencil-benchmark,rbaghdadi/pencil-benchmark,pencil-language/pencil-benchmark,dividiti/pencil-benchmark,dividiti/pencil-benchmark,dividiti/pencil-benchmark,pencil-language/pencil-benchmark