Install cython in create_virtualenv function

Signed-off-by: Jono Yang <[email protected]>

Author: JonoYang

configure

@@ -242,6 +242,7 @@ create_virtualenv() {
             --no-vcs-ignore \
             $CFG_QUIET \
             "$CFG_ROOT_DIR/$VENV_DIR"
+        "$CFG_BIN_DIR/pip" install cython
     fi
 }
 
@@ -253,7 +254,6 @@ install_packages() {
     # be reinstalled a second time and reused from the virtualenv and this
     # speeds up the installation.
     # We always have the PEP517 build dependencies installed already.
-    "$CFG_BIN_DIR/pip" install cython
     "$CFG_BIN_DIR/pip" install \
         --upgrade \
         --no-build-isolation \