AC_DEFINE([HAVE_LINUX_VDSO], [1], [Define to 1 if liblinux-vdso is available])
fi
+AC_DEFINE([HAVE_PTHREAD], [1], [Define to 1 if pthread is avaliable])
+
AC_CACHE_CHECK(
[for usable std::is_trivially_copyable],
[folly_cv_decl_std_is_trivially_copyable],