[clang] [compiler-rt] [safestack] Support statically linked executables (PR #190126)

[Fangrui Song via cfe-commits]

MaskRay wrote:

> @MaskRay we don't support static linking with other sanitizers because interceptors and dlsym do not work. Is this safe stack work around is reasonable? Should we consider it for others?

I think this is acceptable since safestack only intercepts one symbol. Other sanitizers have hundreds of interceptors where such workaround may not be maintainable.

https://github.com/llvm/llvm-project/pull/190126