diff --git a/addons/cmake_project.py b/addons/cmake_project.py
index a801178..c266bc2 100644
--- a/addons/cmake_project.py
+++ b/addons/cmake_project.py
@@ -40,10 +40,11 @@ def _generate_cmake_args(env: Environment, dependencies: 'list[dict]') -> 'list[
             args.append(f'-D{name}={cmd_quote(value)}')
     return args
 
-def _calc_version_hash(dependencies: 'list[dict]') -> str:
+def _calc_version_hash(env, dependencies: 'list[dict]') -> str:
     return json.dumps({
         'version': _VERSION,
-        'dependencies': dependencies
+        'dependencies': dependencies,
+        'cxxflags': env['DEPS_CXXFLAGS']
     })
 
 def _cmake_project(env: Environment, project_root: str, generate_args: 'list[str]' = [], build_args : 'list[str]' = [], install_args : 'list[str]' = [], dependencies: 'list[dict]' = []) -> dict:
@@ -51,7 +52,7 @@ def _cmake_project(env: Environment, project_root: str, generate_args: 'list[str
     build_dir = os.path.join(project_root, f'build_{config}')
     install_dir = os.path.join(project_root, f'install_{config}')
 
-    version_hash = _calc_version_hash(dependencies)
+    version_hash = _calc_version_hash(env, dependencies)
     stamp_file = pathlib.Path(install_dir, _BUILT_STAMPFILE)
     is_built = stamp_file.exists()