Update cmake.

python/CMakeLists.txt

@@ -23,10 +23,6 @@ if(UNIX)
   endif()
 endif()
 
-## include pybind
-set(PYBIND11_DIR ${PROJECT_SOURCE_DIR}/../external/pybind11 CACHE PATH "Path to pybind11")
-add_subdirectory(${PYBIND11_DIR} pybind11)
-
 ## include libigl
 option(LIBIGL_USE_STATIC_LIBRARY "Use LibIGL as static library" OFF)
 option(LIBIGL_WITH_OPENGL            "Use viewer"         ON)
@@ -52,6 +48,10 @@ if(NOT TARGET igl::core)
   include(libigl)
 endif()
 
+## include pybind
+set(PYBIND11_DIR ${PROJECT_SOURCE_DIR}/../external/pybind11 CACHE PATH "Path to pybind11")
+add_subdirectory(${PYBIND11_DIR} pybind11)
+
 ## Prepare the python library
 pybind11_add_module(pyigl
   python_shared.cpp