Use dynamic version of Boost with Python bindings.

cmake/libigl.cmake

@@ -197,7 +197,11 @@ if(LIBIGL_WITH_CGAL)
     if(EXISTS ${LIBIGL_EXTERNAL}/boost)
       set(BOOST_ROOT "${LIBIGL_EXTERNAL}/boost")
     endif()
-    option(CGAL_Boost_USE_STATIC_LIBS "Use static Boost libs with CGAL" ON)
+    if(LIBIGL_WITH_PYTHON)
+      option(CGAL_Boost_USE_STATIC_LIBS "Use static Boost libs with CGAL" OFF)
+    else()
+      option(CGAL_Boost_USE_STATIC_LIBS "Use static Boost libs with CGAL" ON)
+    endif()
     find_package(CGAL CONFIG COMPONENTS Core PATHS ${CGAL_DIR} NO_DEFAULT_PATH)
   endif()