Windows GUI: Upgrade to C++Builder 12 Community Edition

[cjee21]

• Save project file with C++Builder 12
  • Clean-up and save project file using C++Builder 12
• Enable Win64x target platform
  • Enable the newer toolchain that is based on LLVM/Clang 15.0 (comparison).
  • To build this version, use changes in Upgrade to C++Builder 12 and enable Win64 and Win64x targets ZenLib#158 and build Win64x targets for zlib, ZenLib and MediaInfo by changing Win64 to Win64x in BuildRelease.bat.
• Various fixes and improvements
  • To make it compile and run successfully on the new C++Builder and Win64x target.

Note:
Looks like it is still not possible to enable CFG and CET even though the new bcc64x toolchain is based on LLVM/Clang 15.0.