Fix version inclusion with Clang

Author: ruberith

CMakeLists.txt

@@ -40,6 +40,9 @@ endif()
 ## Eigen3 is used by most of the libraries that follow
 find_package(Eigen3 REQUIRED)
 add_definitions(-DEIGEN_DISABLE_UNALIGNED_ARRAY_ASSERT)
+if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -idirafter${EIGEN3_INCLUDE_DIR}")
+endif()
 
 ################################################################################
 # own external libraries

Utilities/CMakeLists.txt

@@ -29,5 +29,9 @@ add_library(Utilities
 )
 
 add_dependencies(Utilities partio zlib)
-target_include_directories(Utilities PUBLIC ${TOPLEVEL_INCLUDE_DIR} ${EIGEN3_INCLUDE_DIR})
+if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+	target_compile_options(Utilities PUBLIC -idirafter${TOPLEVEL_INCLUDE_DIR} -idirafter${EIGEN3_INCLUDE_DIR})
+else()
+	target_include_directories(Utilities PUBLIC ${TOPLEVEL_INCLUDE_DIR} ${EIGEN3_INCLUDE_DIR})
+endif()
 target_link_libraries(Utilities INTERFACE partio zlib MD5)