It looks a likely solution. I will have to try on the complete program. Any thoughts on what is happening? I will pass your idea on to Embarcadero, maybe they will have some thoughts.

I have created a new Toy project derived from the original program with dependencies removed and basically only header files remaining. On compiling the error occurs. The toy program uses TeeChart Pro. I have sent the program to Embarcadero but they don't have access to TeeChart Pro. I tried to atta...

An old project. Developed incrementally over 15 plus years. If I had to rewrite from scratch I would be tempted to use Visual Studio.
I did build a toy project and didn't have the problem.
I can fix the error error on single components but it re-occurs on a project compile.

I have a large program, using C++Builder, that has been built over many years. Recently I compiled the program using RAD Studio 11.1 using the “traditional compiler” with no problems. I now need to compile using the latest Clang 32bit compiler. The problem is a compiler error relating to ...\windows...