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

lib/Basic/Targets.cpp

@@ -3847,6 +3847,7 @@ public:
     if (Opts.CPlusPlus)
       Builder.defineMacro("_GNU_SOURCE");
 
+    Builder.defineMacro("__LITTLE_ENDIAN__");
     Builder.defineMacro("__native_client__");
     getArchDefines(Opts, Builder);
   }

test/Driver/le32-unknown-nacl.cpp

@@ -40,6 +40,11 @@ int align_ld = __alignof(long double);
 // CHECK: @align_vl = global i32 4
 int align_vl = __alignof(va_list);
 
+// CHECK: __LITTLE_ENDIAN__defined
+#ifdef __LITTLE_ENDIAN__
+void __LITTLE_ENDIAN__defined() {}
+#endif
+
 // CHECK: __native_client__defined
 #ifdef __native_client__
 void __native_client__defined() {}