--- cmake/modules/PythonMacros.cmake.orig	2012-05-31 23:28:04.035788719 +0200
+++ cmake/modules/PythonMacros.cmake	2012-05-31 23:30:13.997840354 +0200
@@ -24,39 +24,41 @@
   INSTALL(FILES ${SOURCE_FILE} DESTINATION ${DESINATION_DIR})
 
   # Byte compile and install the .pyc file.        
-  GET_FILENAME_COMPONENT(_absfilename ${SOURCE_FILE} ABSOLUTE)
-  GET_FILENAME_COMPONENT(_filename ${SOURCE_FILE} NAME)
-  GET_FILENAME_COMPONENT(_filenamebase ${SOURCE_FILE} NAME_WE)
-  GET_FILENAME_COMPONENT(_basepath ${SOURCE_FILE} PATH)
-
-  if(WIN32)
-    string(REGEX REPLACE ".:/" "/" _basepath "${_basepath}")
-  endif(WIN32)
-
-  SET(_bin_py ${CMAKE_CURRENT_BINARY_DIR}/${_basepath}/${_filename})
-  SET(_bin_pyc ${CMAKE_CURRENT_BINARY_DIR}/${_basepath}/${_filenamebase}.pyc)
-
-  FILE(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${_basepath})
-
-  SET(_message "-DMESSAGE=Byte-compiling ${_bin_py}")
-
-  GET_FILENAME_COMPONENT(_abs_bin_py ${_bin_py} ABSOLUTE)
-  IF(_abs_bin_py STREQUAL ${_absfilename})    # Don't copy the file onto itself.
-    ADD_CUSTOM_COMMAND(
-      TARGET compile_python_files
-      COMMAND ${CMAKE_COMMAND} -E echo ${_message}
-      COMMAND ${PYTHON_EXECUTABLE} ${_python_compile_py} ${_bin_py}
-      DEPENDS ${_absfilename}
-    )
-  ELSE(_abs_bin_py STREQUAL ${_absfilename})
-    ADD_CUSTOM_COMMAND(
-      TARGET compile_python_files
-      COMMAND ${CMAKE_COMMAND} -E echo ${_message} 
-      COMMAND ${CMAKE_COMMAND} -E copy ${_absfilename} ${_bin_py}
-      COMMAND ${PYTHON_EXECUTABLE} ${_python_compile_py} ${_bin_py}
-      DEPENDS ${_absfilename}
-    )
-  ENDIF(_abs_bin_py STREQUAL ${_absfilename})
+  IF("$ENV{PYTHONDONTWRITEBYTECODE}" STREQUAL "")
+    GET_FILENAME_COMPONENT(_absfilename ${SOURCE_FILE} ABSOLUTE)
+    GET_FILENAME_COMPONENT(_filename ${SOURCE_FILE} NAME)
+    GET_FILENAME_COMPONENT(_filenamebase ${SOURCE_FILE} NAME_WE)
+    GET_FILENAME_COMPONENT(_basepath ${SOURCE_FILE} PATH)
+
+    if(WIN32)
+      string(REGEX REPLACE ".:/" "/" _basepath "${_basepath}")
+    endif(WIN32)
+
+    SET(_bin_py ${CMAKE_CURRENT_BINARY_DIR}/${_basepath}/${_filename})
+    SET(_bin_pyc ${CMAKE_CURRENT_BINARY_DIR}/${_basepath}/${_filenamebase}.pyc)
+
+    FILE(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${_basepath})
+
+    SET(_message "-DMESSAGE=Byte-compiling ${_bin_py}")
+
+    GET_FILENAME_COMPONENT(_abs_bin_py ${_bin_py} ABSOLUTE)
+    IF(_abs_bin_py STREQUAL ${_absfilename})    # Don't copy the file onto itself.
+      ADD_CUSTOM_COMMAND(
+        TARGET compile_python_files
+        COMMAND ${CMAKE_COMMAND} -E echo ${_message}
+        COMMAND ${PYTHON_EXECUTABLE} ${_python_compile_py} ${_bin_py}
+        DEPENDS ${_absfilename}
+      )
+    ELSE(_abs_bin_py STREQUAL ${_absfilename})
+      ADD_CUSTOM_COMMAND(
+        TARGET compile_python_files
+        COMMAND ${CMAKE_COMMAND} -E echo ${_message} 
+        COMMAND ${CMAKE_COMMAND} -E copy ${_absfilename} ${_bin_py}
+        COMMAND ${PYTHON_EXECUTABLE} ${_python_compile_py} ${_bin_py}
+        DEPENDS ${_absfilename}
+      )
+    ENDIF(_abs_bin_py STREQUAL ${_absfilename})
 
-  INSTALL(FILES ${_bin_pyc} DESTINATION ${DESINATION_DIR})
+    INSTALL(FILES ${_bin_pyc} DESTINATION ${DESINATION_DIR})
+  ENDIF("$ENV{PYTHONDONTWRITEBYTECODE}" STREQUAL "")
 ENDMACRO(PYTHON_INSTALL)