[clang] [flang] [driver] Generalize the code that adds the path of libflang_rt.runtime.a. (PR #134362)

[Fangrui Song via cfe-commits]

================
@@ -2,7 +2,7 @@
 ! invocation. These libraries are added on top of other standard runtime
 ! libraries that the Clang driver will include.
 
-! RUN: %flang -### --target=ppc64le-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,UNIX,UNIX-F128NONE
+! RUN: %flang -### --target=ppc64le-linux-gnu %S/Inputs/hello.f90 2>&1 | FileCheck %s --check-prefixes=CHECK,UNIX,UNIX-F128%f128-lib
----------------
MaskRay wrote:

This `%` syntax looks unusual. Does it work?

https://github.com/llvm/llvm-project/pull/134362