[llvm] [llvm-config] Quote and escape paths if necessary (PR #97305)

[Alexandre Ganea via llvm-commits]

aganea wrote:

> Example of subtle breakage: cctools-port ld64's support for LTO breaks for some reason because of this change.

Are you able to debug what is wrong there? Maybe because [they are collating path components](https://github.com/tpoechtrager/cctools-port/blob/856d7d1bfcc890357bfe79b3f4aa206a0487b416/tools/fix_liblto.sh#L26) to an already quoted path, and the bintools don't like that? (this works on Windows with cl.exe and clang-cl.exe at least).

I think that if we don't introduce a breaking change with LLVM 19 in this regards (quoted strings emitted by `llvm-config`), this patch will be worthless. When quoted strings will be required, it won't work (as you're pointing out) in the downstream usages. Evidently some of the paths emitted by `llvm-config` might not require escaping, since they are alone on a single line, and could be quoted later by consuming scripts.

Any other suggestions?

+ at MaskRay 

https://github.com/llvm/llvm-project/pull/97305