Use a specific python version if specified

CMakeLists.txt

@@ -58,26 +58,8 @@ else()
 endif()
 
 # load python and pybind11
+include(Python)
 include(pybind11)
-if(CMAKE_VERSION VERSION_LESS 3.12.0)
-    if(Python_ROOT_DIR)
-        MESSAGE(WARNING "Python_ROOT_DIR is set but will be ignored by this version of CMake; set PYTHON_EXECUTABLE instead")
-	endif()
-	find_package(PythonInterp)
-	find_package(PythonLibs)
-	set(PYTHON_FOUND PYTHONLIBS_FOUND AND PYTHONINTERP_FOUND)
-else()
-    if(PYTHON_EXECUTABLE)
-        MESSAGE(WARNING "PYTHON_EXECUTABLE is set but will be ignored by this version of CMake; set Python_ROOT_DIR instead")
-	endif()
-    find_package(Python COMPONENTS Interpreter Development)
-    set(PYTHON_FOUND Python_Interpreter_FOUND AND Python_Development_FOUND)
-    set(PYTHON_EXECUTABLE "${Python_EXECUTABLE}")
-	set(PYTHON_INCLUDE_DIRS "${Python_INCLUDE_DIRS}")
-	set(PYTHON_LIBRARIES "${Python_LIBRARIES}")
-	set(PYTHON_VERSION_MAJOR "${Python_VERSION_MAJOR}")
-	set(PYTHON_VERSION_MINOR "${Python_VERSION_MINOR}")
-endif()
 
 # load project dependencies
 include(rk)

cmake/Packages/Python.cmake

@@ -2,14 +2,23 @@ IF(CMAKE_VERSION VERSION_LESS 3.12.0)
     IF(Python_ROOT_DIR)
         MESSAGE(WARNING "Python_ROOT_DIR is set but will be ignored by this version of CMake; set PYTHON_EXECUTABLE instead")
     ENDIF(Python_ROOT_DIR)
-    find_package(PythonInterp)
-    find_package(PythonLibs)
+    IF(PYTHON_VERSION)
+        find_package(PythonInterp ${PYTHON_VERSION})
+        find_package(PythonLibs ${PYTHON_VERSION})
+    ELSE(PYTHON_VERSION)
+      find_package(PythonInterp)
+      find_package(PythonLibs)
+    ENDIF(PYTHON_VERSION)
     set(PYTHON_FOUND PYTHONLIBS_FOUND AND PYTHONINTERP_FOUND)
 ELSE()
     IF(PYTHON_EXECUTABLE)
         MESSAGE(WARNING "PYTHON_EXECUTABLE is set but will be ignored by this version of CMake; set Python_ROOT_DIR instead")
     ENDIF(PYTHON_EXECUTABLE)
-    FIND_PACKAGE(Python COMPONENTS Interpreter Development)
+    IF(PYTHON_VERSION)
+      FIND_PACKAGE(Python ${PYTHON_VERSION} COMPONENTS Interpreter Development)
+    ELSE(PYTHON_VERSION)
+      FIND_PACKAGE(Python COMPONENTS Interpreter Development)
+    ENDIF(PYTHON_VERSION)
     SET(PYTHON_FOUND "${Python_FOUND}")
     SET(PYTHON_EXECUTABLE "${Python_EXECUTABLE}")
     SET(PYTHON_INCLUDE_DIRS "${Python_INCLUDE_DIRS}")