Emphasize in guides that all this is optional.

0206-Compilation-PETSc-Windows.md

 Compilation Guide for INMOST with PETSc linear solvers
 =====
 
+INMOST may be configured with optional PETSc support. In this case INMOST will support calling linear solvers from PETSc package, i.e. you will be able to activate Solver::PETSc package in Solver::Solver constructor.
 
 Download PETSc from [http://www.mcs.anl.gov/petsc/download/index.html](http://www.mcs.anl.gov/petsc/download/index.html) and unarchive to petsc_source_path. This guide is tested with PETSc version 3.5.2.
 
@@ -122,7 +123,7 @@ Now hit "Configure". Wait some time while PETSc run some tests and decide on com
 [[pics/compile_petsc_10.png]]
 
 
-Now click "Generate", reopen Visual Studio with INMOST library and rebuild it. Now you will be able to activate Solver::PETSC package in Solver::Solver constructor.
+Now click "Generate", reopen Visual Studio with INMOST library and rebuild it.
 
 
 Please note that the cmake script for PETSc package that is used here was modified in order to handle spaces in names and correctly resolve required Cygwin executables. If you encounter any problem you can visit [https://github.com/jedbrown/cmake-modules/](https://github.com/jedbrown/cmake-modules/) page and replace