setExecutable() should default to success if there's nothing custom for it.

llvm-svn: 127891
diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
index 4312d67..5a57a28 100644
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -124,7 +124,7 @@
     (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
   return KERN_SUCCESS == kr;
 #else
-  return false;
+  return true;
 #endif
 }