Let hipcc not pass -mllvm option to HIP-Clang on Windows

Currently there is a clang bug on Windows causing duplicate -mllvm options in clang -cc1.

Tempoarily disable -mllvm options for HIP-Clang on Windows until the bug is fixed.

Change-Id: I3a4393ba7745989398dc6c6001722837dad18704

bin/hipcc

@@ -726,10 +726,12 @@ if ($HIP_PLATFORM eq "clang") {
         $HIPCXXFLAGS .= " -O3";
         $HIPLDFLAGS .= " -O3";
     }
-    if ($optArg ne "-O0") {
-       $HIPCXXFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";
-       if ($needLDFLAGS and not $needCXXFLAGS) {
-           $HIPLDFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";
+    # Do not pass -mllvm on Windows since there is a clang bug causing duplicate -mllvm options in clang -cc1 on Windows.
+    # ToDo : remove restriction for Windows after clang bug is fixed.
+    if ($optArg ne "-O0" and not $isWindows) {
+        $HIPCXXFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";
+        if ($needLDFLAGS and not $needCXXFLAGS) {
+            $HIPLDFLAGS .= " -mllvm -amdgpu-early-inline-all=true -mllvm -amdgpu-function-calls=false";
         }
     }
     $HIP_DEVLIB_FLAGS = " --hip-device-lib-path=$DEVICE_LIB_PATH";