Driver: Fix possible crash when targetting an unknown (unsupported) Darwin
platform, e.g. ppc.

llvm-svn: 99016
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 86b4685..58a4cdb 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -655,6 +655,12 @@
   } else {
     const toolchains::Darwin &DarwinTC(
       reinterpret_cast<const toolchains::Darwin&>(TC));
+
+    // If the target isn't initialized (e.g., an unknown Darwin platform, return
+    // the default triple).
+    if (!DarwinTC.isTargetInitialized())
+      return Triple.getTriple();
+    
     unsigned Version[3];
     DarwinTC.getTargetVersion(Version);