Define __LITTLE_ENDIAN__ for le32, since "le" stands for little endian.
Add a test for this too.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153616 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 73bd2b6..f05b9c1 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -3847,6 +3847,7 @@
     if (Opts.CPlusPlus)
       Builder.defineMacro("_GNU_SOURCE");
 
+    Builder.defineMacro("__LITTLE_ENDIAN__");
     Builder.defineMacro("__native_client__");
     getArchDefines(Opts, Builder);
   }