[compiler-rt] Add CMake option to enable execute-only code generation on AArch64 (#140555)

For a full toolchain supporting execute-only code generation the runtime
libraries also need to be pre-compiled with it enabled. The generic
`RUNTIMES_EXECUTE_ONLY_CODE` CMake option can now be used during build
configuration to enable execute-only code generation in compiler-rt.

The build option can only be enabled for a runtimes build of
compiler-rt, because a recent version of Clang is needed to correctly
compile assembly files with execute-only code support.

Related RFC:
https://discourse.llvm.org/t/rfc-execute-only-code-support-for-runtime-libraries-on-aarch64/86180

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GitOrigin-RevId: 9d18e92ee78c4171477d5a868bd8ad3c1dbf07a1
1 file changed