Silence warning in Release builds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index b997786..80de55e 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -44,6 +44,7 @@
 
   error_code EC = llvm::sys::fs::current_path(CompilationDir);
   assert(!EC && "Could not determine the current directory");
+  (void)EC;
 
   MachOUniquingMap = 0;
   ELFUniquingMap = 0;