Flip sense of option.

mlir/CMakeLists.txt

@@ -163,8 +163,8 @@ configure_file(
 #   The pybind11 library can be found (set with -DPYBIND_DIR=...)
 #   The python executable is correct (set with -DPython3_EXECUTABLE=...)
 # By default, find_package and probing for installed pybind11 is performed.
-# Super projects can set MLIR_CONFIGURE_PYTHON_DEV_PACKAGES to disable all
-# package setup and control it themselves.
+# Super projects can set MLIR_DISABLE_CONFIGURE_PYTHON_DEV_PACKAGES=ON to 
+# disable all package setup and control it themselves.
 #-------------------------------------------------------------------------------
 
 set(MLIR_ENABLE_BINDINGS_PYTHON 0 CACHE BOOL
@@ -173,7 +173,7 @@ set(MLIR_DETECT_PYTHON_ENV_PRIME_SEARCH 1 CACHE BOOL
        "Prime the python detection by searching for a full 'Development' \
        component first (temporary while diagnosing environment specific Python \
        detection issues)")
-set(MLIR_CONFIGURE_PYTHON_DEV_PACKAGES 1 CACHE BOOL
+set(MLIR_DISABLE_CONFIGURE_PYTHON_DEV_PACKAGES 0 CACHE BOOL
        "Performs python dev package configuration sufficient to use all MLIR \
        python features. Super-projects that wish to control their own setup \
        must perform an appropriate find_package of Python3 with \

mlir/cmake/modules/MLIRDetectPythonEnv.cmake

@@ -2,7 +2,7 @@
 
 # Finds and configures python packages needed to build MLIR Python bindings.
 macro(mlir_configure_python_dev_packages)
-  if(MLIR_CONFIGURE_PYTHON_DEV_PACKAGES)
+  if(NOT MLIR_DISABLE_CONFIGURE_PYTHON_DEV_PACKAGES)
     if(MLIR_DETECT_PYTHON_ENV_PRIME_SEARCH)
       # Prime the search for python to see if there is a full development
       # package. This seems to work around cmake bugs searching only for