Subzero: Move to C++11 static_assert().

BUG= none
R=jvoung@chromium.org, kschimpf@google.com

Review URL: https://codereview.chromium.org/618313003
diff --git a/src/IceIntrinsics.cpp b/src/IceIntrinsics.cpp
index 757455f..6e2448d 100644
--- a/src/IceIntrinsics.cpp
+++ b/src/IceIntrinsics.cpp
@@ -23,11 +23,10 @@
 
 namespace Ice {
 
-namespace {
+static_assert(sizeof(Intrinsics::IntrinsicInfo) == 4,
+              "Unexpected sizeof(IntrinsicInfo)");
 
-void __attribute__((unused)) xIntrinsicInfoSizeCheck() {
-  STATIC_ASSERT(sizeof(Intrinsics::IntrinsicInfo) == 4);
-}
+namespace {
 
 #define INTRIN(ID, SE, RT) { Intrinsics::ID, Intrinsics::SE, Intrinsics::RT }