[A+A] fix swdev-283654 548.exchange2_r and 648.exchange2_s fails building

Over constrained the previous fix for detecting when to invoke the
closed compiler based on options.  There is a SPEC CPU invocation 548
and 658 (same sources) that triggers based on -fveclib=AMDLIBM

Change-Id: I688a11119366539d7ccf4843ef3a3103036c437d

Author: ronlieb

clang/lib/Driver/ToolChains/AmdOptArgs.cpp

@@ -132,9 +132,12 @@ static bool checkForPropOpts(const ToolChain &TC, const Driver &D,
                      Args.MakeArgString("-vector-library=LIBMVEC-X86"));
           break;
         }
+        // fveclib supported prior to amd-opt, if its AMDLIBM then
+        // we want to trigger closed compiler, otherwise not.
+        if (Name == "AMDLIBM")
+          ClosedToolChainNeeded = true;
       }
     }
-    // fveclib supported prior to amd-opt, so not a trigger for closed.
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_fstruct_layout_EQ)) {