fix outdated file path ref in llvm

This was added years ago and is outdated today.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

src/bootstrap/src/core/build_steps/llvm.rs

@@ -1338,7 +1338,7 @@ impl Step for CrtBeginEnd {
             .file(crtbegin_src)
             .file(crtend_src);
 
-        // Those flags are defined in src/llvm-project/compiler-rt/lib/crt/CMakeLists.txt
+        // Those flags are defined in src/llvm-project/compiler-rt/lib/builtins/CMakeLists.txt
         // Currently only consumer of those objects is musl, which use .init_array/.fini_array
         // instead of .ctors/.dtors
         cfg.flag("-std=c11")