Tweak a couple of assert(3) calls.

Fixes #132.

Change-Id: I0cf3b016fbf304ac53e04fc6b75a536cd9d755b1
Reviewed-on: https://code-review.googlesource.com/10950
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/util/sparse_array.h b/util/sparse_array.h
index b9853a7..eb0498e 100644
--- a/util/sparse_array.h
+++ b/util/sparse_array.h
@@ -273,7 +273,7 @@
   iterator SetInternal(bool allow_overwrite, int i, U&& v) {  // NOLINT
     DebugCheckInvariants();
     if (static_cast<uint32_t>(i) >= static_cast<uint32_t>(max_size_)) {
-      assert(!"illegal index");
+      assert(false && "illegal index");
       // Semantically, end() would be better here, but we already know
       // the user did something stupid, so begin() insulates them from
       // dereferencing an invalid pointer.
diff --git a/util/sparse_set.h b/util/sparse_set.h
index b431643..191ac7c 100644
--- a/util/sparse_set.h
+++ b/util/sparse_set.h
@@ -132,7 +132,7 @@
   iterator InsertInternal(bool allow_existing, int i) {
     DebugCheckInvariants();
     if (static_cast<uint32_t>(i) >= static_cast<uint32_t>(max_size_)) {
-      assert(!"illegal index");
+      assert(false && "illegal index");
       // Semantically, end() would be better here, but we already know
       // the user did something stupid, so begin() insulates them from
       // dereferencing an invalid pointer.