[llvm] [cmake] Optimize RelWithDebInfo compiler options on windows (PR #101533)

[via llvm-commits]

zmodem wrote:

Where are the flags for RelWithDebInfo currently defined? Is that done in LLVM's CMake files somewhere, or is it CMake internal?

This patch adds a bunch of flags. The ideal would be if RelWithDebInfo was equivalent to Release + flags to build the .pdb.

> In addition, cross-compilation should require additional parameters to be set

What does this mean?

https://github.com/llvm/llvm-project/pull/101533