[Backport] More potential leak fixes and build fix

(adapted from commit MeVisLab/pythonqt@525ea41)

Since the changes to "src/PythonQt.cpp" are reverted through
e01fe14 (Revert "More potential leak fixes and build fix"),
this commit only backports the changes to "build/python.prf".

Author: gregor-anich-uibk

build/python.prf

@@ -8,41 +8,43 @@ isEmpty( PYTHON_VERSION ) {
   unix:PYTHON_VERSION=2.7
 }
 
-
-macx {
-  # for macx you need to have the Python development kit installed as framework
-  INCLUDEPATH += /System/Library/Frameworks/Python.framework/Headers
-  LIBS += -F/System/Library/Frameworks -framework Python
-} else:win32 {
-  # for windows install a Python development kit or build Python yourself from the sources
-  # Make sure that you set the environment variable PYTHON_PATH to point to your
-  # python installation (or the python sources/header files when building from source).
-  # Make sure that you set the environment variable PYTHON_LIB to point to
-  # the directory where the python libs are located.
-  #
-  # When using the prebuild Python installer, this will be:
-  # set PYTHON_PATH = c:\Python26
-  # set PYTHON_LIB  = c:\Python26\libs
-  #
-  # When using the python sources, this will be something like:
-  # set PYTHON_PATH = c:\yourDir\Python-2.6.1\
-  # set PYTHON_LIB  = c:\yourDir\Python-2.6.1\PCbuild8\Win32
-
-  # check if debug or release
-  CONFIG(debug, debug|release) {
-    DEBUG_EXT = _d 
-  } else {
-    DEBUG_EXT = 
-  }
-
-  win32:INCLUDEPATH += $$(PYTHON_PATH)/PC $$(PYTHON_PATH)/include
-  win32:LIBS += $$(PYTHON_LIB)/python$${PYTHON_VERSION}$${DEBUG_EXT}.lib
-} else:unix {
-  # on linux, python-config is used to autodetect Python.
-  # make sure that you have installed a matching python-dev package.
+message(Using Python version $${PYTHON_VERSION})
+
+macx {
+  # for macx you need to have the Python development kit installed as framework
+  INCLUDEPATH += /System/Library/Frameworks/Python.framework/Headers
+  LIBS += -F/System/Library/Frameworks -framework Python
+} else:win32 {
+  # for windows install a Python development kit or build Python yourself from the sources
+  # Make sure that you set the environment variable PYTHON_PATH to point to your
+  # python installation (or the python sources/header files when building from source).
+  # Make sure that you set the environment variable PYTHON_LIB to point to
+  # the directory where the python libs are located.
+  #
+  # When using the prebuild Python installer, this will be:
+  # set PYTHON_PATH = c:\Python26
+  # set PYTHON_LIB  = c:\Python26\libs
+  #
+  # When using the python sources, this will be something like:
+  # set PYTHON_PATH = c:\yourDir\Python-2.6.1\
+  # set PYTHON_LIB  = c:\yourDir\Python-2.6.1\PCbuild8\Win32
+
+  # check if debug or release
+  CONFIG(debug, debug|release) {
+    DEBUG_EXT = _d 
+  } else {
+    DEBUG_EXT = 
+  }
+
+  win32:INCLUDEPATH += $$(PYTHON_PATH)/PC $$(PYTHON_PATH)/include
+  win32:LIBS += $$(PYTHON_LIB)/python$${PYTHON_VERSION}$${DEBUG_EXT}.lib
+} else:unix {
+  # on linux, python-config is used to autodetect Python.
+  # make sure that you have installed a matching python-dev package.
 
   system(python$${PYTHON_VERSION}-config --embed --libs) {
     unix:LIBS += $$system(python$${PYTHON_VERSION}-config --embed --libs)
   } else: unix:LIBS += $$system(python$${PYTHON_VERSION}-config --libs)  
-  unix:QMAKE_CXXFLAGS += $$system(python$${PYTHON_VERSION}-config --includes)
-}
+  unix:QMAKE_CXXFLAGS += $$system(python$${PYTHON_VERSION}-config --includes)
+  unix:QMAKE_LFLAGS += $$system(python$${PYTHON_VERSION}-config --ldflags)
+}