[clang] [Driver] Find vendor-prefixed musl GCC toolchains (PR #206477)

[Adeel Mujahid via cfe-commits]

================
@@ -71,17 +71,6 @@ C/C++ Language Potentially Breaking Changes
   Clang would previously ``break`` out of the ``while`` loop, whereas GCC (since version 9) would
   ``break`` out of the ``for`` loop here. Now, Clang and GCC both break out of the ``for`` loop.
 
-- Clang now parses line and digit directives, module names, and original filenames as unevaluated
-  strings. This means that code containing strings with escape sequences such as
-
-  .. code-block:: c++
-
-    # 1 "original\x12source.c"
-    #pragma clang module import "\x41"
-    # 50 "a\012.c"
-
-  are now ill-formed.
-
 C++ Specific Potentially Breaking Changes
----------------
am11 wrote:

```suggestion

- Clang now parses line and digit directives, module names, and original filenames as unevaluated
  strings. This means that code containing strings with escape sequences such as

  .. code-block:: c++

    # 1 "original\x12source.c"
    #pragma clang module import "\x41"
    # 50 "a\012.c"

  are now ill-formed.

C++ Specific Potentially Breaking Changes
```

https://github.com/llvm/llvm-project/pull/206477