CHIA-3718 Handle building chiavdf for MacOS when CMake is already installed (#20018) (#20032)

Author: altendky

install-timelord.sh

@@ -113,8 +113,11 @@ else
     symlink_vdf_bench "$PYTHON_VERSION"
   elif [ -e venv/bin/python ] && test "$MACOS"; then
     echo "Installing chiavdf dependencies for MacOS."
+    if ! cmake --version >/dev/null 2>&1; then
+      brew install --formula --quiet cmake
+    fi
     # The most recent boost version causes compile errors.
-    brew install --formula --quiet [email protected] cmake gmp
+    brew install --formula --quiet [email protected] gmp
     # [email protected] is keg-only, which means it was not symlinked into /usr/local,
     # because this is an alternate version of another formula.
     export LDFLAGS="-L/usr/local/opt/[email protected]/lib"