--- CMakeLists.txt.orig	2026-07-31 12:30:19 UTC
+++ CMakeLists.txt
@@ -449,6 +449,7 @@ if(WITH_CORE)
   IF(WITH_INTERNAL_SPATIALINDEX)
     message(STATUS "Using internal spatialindex")
     set(SPATIALINDEX_INCLUDE_DIR ${CMAKE_SOURCE_DIR}/external/spatialindex/include)
+    include_directories(BEFORE SYSTEM ${CMAKE_SOURCE_DIR}/external/spatialindex/include)
   else()
     find_package(Spatialindex REQUIRED)
     if(SPATIALINDEX_VERSION VERSION_GREATER_EQUAL "2.1")