diff --git a/external/backtrace-cpp/CMakeLists.txt b/external/backtrace-cpp/CMakeLists.txt
index bf6aa6e..c9ae155 100644
--- a/external/backtrace-cpp/CMakeLists.txt
+++ b/external/backtrace-cpp/CMakeLists.txt
@@ -37,6 +37,9 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_COMPILER_IS_GNUCXX)
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g")
 endif()
 
+# ANBOX: allow old-style casts
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-error=old-style-cast")
+
 ###############################################################################
 # BACKWARD OBJECT
 ###############################################################################
@@ -109,4 +112,4 @@ install(
 install(
     FILES "BackwardConfig.cmake"
     DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/backward
-)
\ No newline at end of file
+)