[cmake] Use `GNUInstallDirs` to support custom installation dirs.
-rw-r--r-- 219 .arcconfig
-rw-r--r-- 437 .arclint
-rw-r--r-- 19 .clang-format
-rw-r--r-- 1038 .clang-tidy
-rw-r--r-- 1611 .git-blame-ignore-revs
drwxr-xr-x - .github
-rw-r--r-- 2183 .gitignore
-rw-r--r-- 1514 .mailmap
-rw-r--r-- 431 CONTRIBUTING.md
-rw-r--r-- 4539 README.md
-rw-r--r-- 205 SECURITY.md
drwxr-xr-x - bolt
drwxr-xr-x - clang-tools-extra
drwxr-xr-x - clang
drwxr-xr-x - cmake
drwxr-xr-x - compiler-rt
drwxr-xr-x - cross-project-tests
drwxr-xr-x - flang
drwxr-xr-x - libc
drwxr-xr-x - libclc
drwxr-xr-x - libcxx
drwxr-xr-x - libcxxabi
drwxr-xr-x - libunwind
drwxr-xr-x - lld
drwxr-xr-x - lldb
drwxr-xr-x - llvm
drwxr-xr-x - mlir
drwxr-xr-x - openmp
drwxr-xr-x - polly
drwxr-xr-x - pstl
drwxr-xr-x - runtimes
drwxr-xr-x - third-party
drwxr-xr-x - utils