Changed code for finding ERT Python

- Using standard python 'import ert' and introspection.
 - Using dist-packages (debian) and site-packages (!debian).
 - In separate cmake module FindERTPython.cmake

cmake/Modules/FindERT.cmake

@@ -72,24 +72,6 @@ find_path (ERT_GEN_INCLUDE_DIR
   ${_no_default_path}
   )
 
-find_package(PythonInterp)
-if(PYTHONINTERP_FOUND)
-  execute_process ( COMMAND ${PYTHON_EXECUTABLE} -c
-                            "from distutils.sysconfig import get_python_lib; print get_python_lib()" 
-                    OUTPUT_VARIABLE PYTHON_SITE_PACKAGES OUTPUT_STRIP_TRAILING_WHITESPACE)
-  find_path (ERT_PYTHON_PATH
-    NAMES "ert/__ert_lib_path.py"
-    HINTS "${ERT_ROOT}"
-    PATHS "${PYTHON_SITE_PACKAGES}"
-          "${PROJECT_SOURCE_DIR}/../ert/build/lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/dist-packages"
-          "${PROJECT_SOURCE_DIR}/../ert/devel/build/lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/dist-packages"
-          "${PROJECT_BINARY_DIR}/../ert-build/lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/dist-packages"
-          "${PROJECT_BINARY_DIR}/../ert/devel/lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/dist-packages")
-    if(ERT_PYTHON_PATH MATCHES "NOTFOUND")
-      set(ERT_PYTHON_PATH "")
-    endif()
-endif()
-
 
 # need all of these libraries
 if (CMAKE_SIZEOF_VOID_P)
@@ -300,3 +282,7 @@ find_package_handle_standard_args (ERT
   DEFAULT_MSG
   ERT_INCLUDE_DIR ERT_LIBRARY HAVE_ERT
   )
+
+
+
+

cmake/Modules/FindERTPython.cmake

@@ -0,0 +1,55 @@
+# - Find the Python wrappers for Ensemble-based Reservoir Tool (ERT)
+#
+# Set the cache variable ERT_PYTHON_PATH to the install location of
+# the root ert package.  
+
+find_package(PythonInterp)
+if(PYTHONINTERP_FOUND)
+
+# We try to find the ert Python distribution. This is done by running
+# Python code which tries to 'import ert' and prints out the path to
+# the module if the import succeeds.
+#
+# The normal Python import machinery is employed, so if you have
+# installed ert python in a default location, or alternatively set the
+# PYTHONPATH variable the ert Python distribution will eventually be
+# found there, independently of the alternatives which are tested with
+# the ${PATH_LIST} variable.
+
+  if (EXISTS "/etc/debian_version")
+     set( PYTHON_PACKAGE_PATH "dist-packages")
+  else()
+     set( PYTHON_PACKAGE_PATH "site-packages")
+  endif()
+  set(PYTHON_INSTALL_PREFIX  "lib/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/${PYTHON_PACKAGE_PATH}"  CACHE STRING "Subdirectory to install Python modules in")
+
+  if (ERT_ROOT)
+     set( start_path "${ERT_ROOT}/${PYTHON_INSTALL_PREFIX}" )
+  else()
+     set( start_path "DEFAULT_PATH")
+  endif()
+
+  set( PATH_LIST "${start_path}"
+                 "${PROJECT_SOURCE_DIR}/../ert/build/${PYTHON_INSTALL_PREFIX}"
+                 "${PROJECT_SOURCE_DIR}/../ert/devel/build/${PYTHON_INSTALL_PREFIX}"
+                 "${PROJECT_BINARY_DIR}/../ert-build/${PYTHON_INSTALL_PREFIX}"
+                 "${PROJECT_BINARY_DIR}/../ert/devel/${PYTHON_INSTALL_PREFIX}")
+
+  foreach( PATH ${PATH_LIST})
+      set( python_code "import sys; sys.path.insert(0 , '${PATH}'); import os.path; import inspect; import ert; print os.path.dirname(os.path.dirname(inspect.getfile(ert)))")
+      execute_process( COMMAND ${PYTHON_EXECUTABLE} -c "${python_code}"
+                       RESULT_VARIABLE import_result
+                       OUTPUT_VARIABLE stdout_output
+                       ERROR_VARIABLE stderr_output
+                       OUTPUT_STRIP_TRAILING_WHITESPACE )
+
+      if (${import_result} EQUAL 0)
+         set( ERT_PYTHON_PATH ${stdout_output} CACHE PATH "Python path for ERT Python" )
+         break()
+      endif()
+   endforeach()
+endif()
+find_package_handle_standard_args("ERTPython" DEFAULT_MSG ERT_PYTHON_PATH)
+
+
+