[libc++] Add check to ensure oss-fuzz properly targets libc++.
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 27ec4abeac4dae65a307c4eb206110ba8c2ca2ce
diff --git a/fuzzing/fuzzing.cpp b/fuzzing/fuzzing.cpp
index d036f0c..7e58dba 100644
--- a/fuzzing/fuzzing.cpp
+++ b/fuzzing/fuzzing.cpp
@@ -39,6 +39,10 @@
#include <cassert>
// If we had C++14, we could use the four iterator version of is_permutation and equal
+#ifndef _LIBCPP_VERSION
+#error These test should be built with libc++ only.
+#endif
+
namespace fuzzing {
// This is a struct we can use to test the stable_XXX algorithms.