conditional boost include

CMakeLists.txt

@@ -20,9 +20,14 @@ endif()
 
 add_library(assimp ${ASSIMP_LINK_TYPE} ${SOURCE_FILES} ${HEADER_FILES})
 
-target_include_directories(assimp PUBLIC
-    code/BoostWorkaround
-)
+if(${Boost_FOUND})
+    target_include_directories(assimp PUBLIC "${Boost_INCLUDE_DIRS}")
+    message("Using installed boost for assimp-lean.")
+else()
+    target_include_directories(assimp PUBLIC code/BoostWorkaround)
+    message("No boost found, using workaround code.")
+endif()
+
 
 target_include_directories(assimp PUBLIC
     include/