diff --git a/configure.ac b/configure.ac
index 69fed451..856d7f17 100644
--- a/configure.ac
+++ b/configure.ac
@@ -383,7 +383,7 @@ AC_CHECK_FUNC(clock_gettime, , [AC_CHECK_LIB(rt, clock_gettime)])
 AC_CHECK_FUNC(fegetenv, , [AC_CHECK_LIB(m, fegetenv)])
 
 AC_CHECK_FUNCS([SecureZeroMemory arc4random arc4random_buf posix_memalign])
-AC_CHECK_FUNCS([memset_s])
+AC_CHECK_FUNCS([memset_s mlock])
 
 AC_SUBST([LIBTOOL_EXTRA_FLAGS])