title: Install PyQt5 and sip fail
body: <p>I created a virtual enviroment with python 2.7 like this:
      virtualenv py_env</p>
  
  <p>Then I wanted to install SIP (sip-4.19.1) and PyQt5 (PyQt-gpl-5.5.1)
  , so I downloaded both (riverbankcomputing) and tried to intall them like so:</p>
  
  <pre><code>cd py_env
  cd sip-4.19.1/
  python configure --incdir=../include/python2.7/
  make
  sudo make install
  </code></pre>
  
  <p>This worked fine and python confirms that sip now can be imported:</p>
  
  <pre><code>&gt;&gt;&gt; import sip
  &gt;&gt;&gt; sip
  &lt;module 'sip' from 
  '/home/robin/Develop/py_todo_env/local/lib/python2.7/site-
  packages/sip.so'&gt;
  </code></pre>
  
  <p>Next, I did this to intall PyQt5:</p>
  
  <pre><code>cd ../PyQt-gpl-5.5.1/
  python configure --sip-incdir=../include/sip/
  make
  ERROR!!!
  </code></pre>
  
  <p>There where errors when running make:</p>
  
  <pre><code>g++ -c -m64 -pipe -fno-exceptions -O2 -Wall -W -D_REENTRANT -fPIC -
  DSIP_PROTECTED_IS_PUBLIC -Dprotected=public -DQT_NO_DEBUG -DQT_PLUGIN -DQT_CORE_LIB -I. -I. -isystem /usr/include/python2.7 -I../qpy/QtCore -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -I. -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -o qpycore_types.o ../qpy/QtCore/qpycore_types.cpp
  ../qpy/QtCore/qpycore_types.cpp: In function ‘int pyqtWrapperType_init(pyqtWrapperType*, PyObject*, PyObject*)’:
  ../qpy/QtCore/qpycore_types.cpp:160:5: error: ‘pyqt5ClassTypeDef’ was not declared in this scope
       pyqt5ClassTypeDef *pyqt_td = (pyqt5ClassTypeDef *)((sipWrapperType *)self)-&gt;type;
       ^
  ../qpy/QtCore/qpycore_types.cpp:160:24: error: ‘pyqt_td’ was not declared in this scope
       pyqt5ClassTypeDef *pyqt_td = (pyqt5ClassTypeDef *)((sipWrapperType *)self)-&gt;type;
                          ^
  ../qpy/QtCore/qpycore_types.cpp:160:54: error: expected primary-expression before ‘)’ token
       pyqt5ClassTypeDef *pyqt_td = (pyqt5ClassTypeDef *)((sipWrapperType *)self)-&gt;type;
                                                        ^
  ../qpy/QtCore/qpycore_types.cpp: In function ‘const QMetaObject* get_qmetaobject(pyqtWrapperType*)’:
  ../qpy/QtCore/qpycore_types.cpp:583:52: error: ‘pyqt5ClassTypeDef’ was not declared in this scope
       return reinterpret_cast&lt;const QMetaObject *&gt;(((pyqt5ClassTypeDef *)((sipWrapperType *)pyqt_wt)-&gt;type)-&gt;static_metaobject);
                                                      ^
  ../qpy/QtCore/qpycore_types.cpp:583:71: error: expected primary-expression before ‘)’ token
       return reinterpret_cast&lt;const QMetaObject *&gt;(((pyqt5ClassTypeDef *)((sipWrapperType *)pyqt_wt)-&gt;type)-&gt;static_metaobject);
                                                                         ^
  Makefile:1892: recipe for target 'qpycore_types.o' failed
  make[1]: *** [qpycore_types.o] Error 1
  make[1]: Leaving directory '/home/robin/Develop/py_todo_env/PyQt-gpl-5.5.1/QtCore'
  Makefile:56: recipe for target 'sub-QtCore-make_first-ordered' failed
  make: *** [sub-QtCore-make_first-ordered] Error 2
  </code></pre>
  
  <p>I have tried different versions of sip and pyqt5, some work, for example pyqt 5.10, but there is no QtWebEngineWidgets module I can import, so something wrong there as well.. Why is it so hard to get this right?</p>