Set the default iOS version to 3.0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156492 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Triple.cpp b/lib/Support/Triple.cpp
index efa2df3..868aa57 100644
--- a/lib/Support/Triple.cpp
+++ b/lib/Support/Triple.cpp
@@ -606,13 +606,15 @@
     // the clang driver combines OS X and IOS support into a common Darwin
     // toolchain that wants to know the iOS version number even when targeting
     // OS X.
-    Major = 0;
+    Major = 3;
     Minor = 0;
     Micro = 0;
     break;
   case IOS:
     getOSVersion(Major, Minor, Micro);
-    // Default to 0.0.
+    // Default to 3.0.
+    if (Major == 0)
+      Major = 3;
     break;
   }
 }