[CMake] Cache the compiler-rt library search results

There's a lot of duplicated calls to find various compiler-rt libraries
from build of runtime libraries like libunwind, libc++, libc++abi and
compiler-rt. The compiler-rt helper module already implemented caching
for results avoid repeated Clang invocations.

This change moves the compiler-rt implementation into a shared location
and reuses it from other runtimes to reduce duplication and speed up
the build.

Differential Revision: https://reviews.llvm.org/D88458

GitOrigin-RevId: 22acda48ff32712746dad3079579f03c6e89e04c
3 files changed
tree: 1d0f523304cc330d1333d8a948a58dd443d0244f
  1. .clang-format
  2. CMakeLists.txt
  4. cmake/
  5. docs/
  6. include/
  7. src/
  8. test/