fix doc main page

HySoP/DoxyConf/mainpage.doxygen

@@ -45,10 +45,10 @@ the libraries versions and so on. That will take place in BUILDDIR.
   -# Change to BUILDDIR and run cmake
 
 \code
-mkdir BUILDIR
-cd BUILDDIR
+mkdir $BUILDIR
+cd $BUILDDIR
 export FC=mpif90
-cmake SOURCEDIR
+cmake $SOURCEDIR
 \endcode
 
 At the end of this step BUILDDIR contains all makefiles, setup.py and other required files for compilation.
@@ -84,9 +84,10 @@ After install completed, new files are located as follows :
 
 \subsubsection installDirConfigCustom Custom configuration
 The other available setup is based on the Python 'Prefix scheme installation' : <a href="http://docs.python.org/2/install/#alternate-installation-unix-the-prefix-scheme">http://docs.python.org/2/install/#alternate-installation-unix-the-prefix-scheme</a>. You need to specify your prefix that replace the default USER_BASE. This prefix is passed to cmake through the variable PREFIX.
-example :
+
+Example :
 \code
-cmake -DPREFIX=/my/custom/prefix
+cmake -DPREFIX=/my/custom/prefix $SOURCEDIR
 \endcode
 After install completed, new files are located as follows :
   - python package in PREFIX/lib/pythonX.Y/site-packages/parmepy/
@@ -111,10 +112,10 @@ make python-install
 
 Default process :
 \code
-mkdir BUILDDIR
-cd BUILDDIR
+mkdir $BUILDDIR
+cd $BUILDDIR
 export FC=mpif90
-cmake SOURCEDIR
+cmake $SOURCEDIR
 make -jN
 make python-install
 \endcode
@@ -130,10 +131,19 @@ Other useful commands :
 \subsection RemarkBrewedPython Note for OSX brewed python :
 If you are using a Python distribution from the <a href="http://brew.sh/">Homebrew</a> package manager for OSX, the --user install option is disbled. Default installation  will fail "error: can't combine user with prefix, exec_prefix/home, or install_(plat)base". Installation require a prefix:
 \code
-cmake -DPREFIX=$(brew --prefix)
+cmake -DPREFIX=$(brew --prefix) $SOURCEDIR
 \endcode
 and it will install package to '$(brew --prefix)/lib/pythonX.Y/site-packages', for example '/usr/local/lib/python2.7/site-packages'
 
+A posible issue is that Python libraries and headers are not correctly discovered by CMake. We invite the user to carefully check that Python stuff in the cmake summary are correct and set the two variables : PYTHON_LIBRARY and PYTHON_INCLUDE_DIR.
+
+For example:
+\code
+cmake -DPYTHON_LIBRARY=$(brew --prefix)/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/Python \
+      -DPYTHON_INCLUDE_DIR=$(brew --prefix)/Cellar/python/2.7.5/Frameworks/Python.framework/Headers \
+      $SOURCEDIR
+\endcode
+
 
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