[clang] [flang] [clang][driver] When -fveclib=ArmPL flag is in use, always link against libamath (PR #116432)

[Paul Walker via cfe-commits]

================
@@ -490,6 +490,16 @@ void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
     else
       A.renderAsInput(Args, CmdArgs);
   }
+  if (const Arg *A = Args.getLastArg(options::OPT_fveclib)) {
+    if (A->getNumValues() == 1) {
+      StringRef V = A->getValue();
+      if (V == "ArmPL") {
+        CmdArgs.push_back(Args.MakeArgString("-lamath"));
+        CmdArgs.push_back(Args.MakeArgString("-lm"));
----------------
paulwalker-arm wrote:

Personally I think things like needing to know the dependencies required by a third party library show why we shouldn't be baking third party libraries into the driver in the first place.  How the library is built is not under llvm's control nor are the libraries part of a recognised operating system.  Are there any existing examples where other third party libraries are baked in?

https://github.com/llvm/llvm-project/pull/116432