Don't link in python if we build without python

src/CMakeLists.txt

@@ -2,6 +2,7 @@ cmake_minimum_required (VERSION 2.6)
 project (phylokit)
 
 OPTION(BUILD_STATIC "build static library (otherwise build shared [ default ])" ON)
+OPTION(BUILD_PYTHON "build static library (otherwise build shared [ default ])" OFF)
 
 file(GLOB SOURCES *.cpp util/*.cpp)
 file(GLOB HEADERS *.hpp)
@@ -14,23 +15,28 @@ add_definitions(-std=c++14 -g -O3 -Wall)
 endif()
 find_package(Boost)
 if(Boost_FOUND)
-  INCLUDE_DIRECTORIES("${Boost_INCLUDE_DIRS}" /usr/include/python2.7)
+  INCLUDE_DIRECTORIES("${Boost_INCLUDE_DIRS}" )
   SET(Boost_USE_STATIC_LIBS OFF)
   SET(Boost_USE_MULTITHREADED ON)
   SET(Boost_USE_STATIC_RUNTIME OFF)
-  FIND_PACKAGE(Boost 1.45.0 COMPONENTS python)
-
-  ADD_LIBRARY(phylokit_python SHARED pyext/bindings.cxx ${SOURCES} )
-  SET_TARGET_PROPERTIES(phylokit_python PROPERTIES OUTPUT_NAME pyphylokit)
-  TARGET_LINK_LIBRARIES(phylokit_python ${Boost_LIBRARIES} )
 
+  if (BUILD_PYTHON)
+    FIND_PACKAGE(Boost 1.45.0 COMPONENTS python)	  
+     INCLUDE_DIRECTORIES(/usr/include/python2.7)
+     ADD_LIBRARY(phylokit_python SHARED pyext/bindings.cxx ${SOURCES} )
+     SET_TARGET_PROPERTIES(phylokit_python PROPERTIES OUTPUT_NAME pyphylokit)
+     TARGET_LINK_LIBRARIES(phylokit_python ${Boost_LIBRARIES} )
+  endif()
 
 
 elseif(NOT Boost_FOUND)
 IF (WIN32)
 INCLUDE_DIRECTORIES("boost/")
 else()
-  INCLUDE_DIRECTORIES("boost/" /usr/include/python2.7)
+  INCLUDE_DIRECTORIES("boost/" )
+  IF (BUILD_PYTHON)
+    INCLUDE_DIRECTORIES(/usr/include/python2.7)
+  ENDIF()
 ENDIF()	
 endif()