Resurrect and modernize C++Builder config

Resurrect and modernize C++Builder config

Similar configuration to what was deleted in 8e56a422, updated for the
unified build scheme. Use the [Clang-based `bcc32c.exe`][1] to avoid a
[bug][2] with the old one, and increase the `tlib.exe` page size to 256.
Also avoid MSVC-specific C runtime library functions.

[1]: http://docwiki.embarcadero.com/RADStudio/Sydney/en/Win32_Clang-enhanced_Compilers
[2]: https://quality.embarcadero.com/browse/RSP-31630

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/13540)