[CMake] Use newer Python find module.

CMakeLists.txt

@@ -235,6 +235,9 @@ option(OGS_ENABLE_ELEMENT_PYRAMID "Build FEM elements for pyramids." ON)
 option(OGS_CHECK_HEADER_COMPILATION "Check header for standalone compilation." OFF)
 
 option(OGS_USE_PYTHON "Interface with Python" OFF)
+if(OGS_USE_PYTHON AND NOT Python_FOUND)
+    message(FATAL_ERROR "Python not found but required for OGS_USE_PYTHON=ON!")
+endif()
 
 option(OGS_USE_MFRONT "Enable solid material models by MFront (https://tfel.sourceforge.net)" OFF)
 

scripts/cmake/Coverage.cmake

@@ -22,7 +22,7 @@ else()
     message(STATUS "No lcov coverage report generated because lcov or genhtml was not found.")
 endif()
 
-if(PYTHON_EXECUTABLE)
+if(Python_EXECUTABLE)
     setup_target_for_coverage_gcovr_xml(
         NAME testrunner_coverage_cobertura
         EXECUTABLE ${CMAKE_COMMAND} --build . --target tests

scripts/cmake/Find.cmake

@@ -9,7 +9,7 @@ find_program(GPROF_PATH gprof DOC "GNU profiler gprof" QUIET)
 
 find_program(CPPCHECK_TOOL_PATH cppcheck)
 
-find_package(PythonInterp QUIET)
+find_package(Python COMPONENTS Interpreter Development)
 
 # Find bash itself ...
 find_program(BASH_TOOL_PATH bash