diff --git a/configure.in b/configure.in
index 2e088734f8..81d4488005 100644
--- a/configure.in
+++ b/configure.in
@@ -2298,6 +2298,7 @@ AC_CHECK_FUNCS(chroot)
 AC_CHECK_FUNCS(chsize)
 AC_CHECK_FUNCS(clock_gettime)
 AC_CHECK_FUNCS(cosh)
+AC_CHECK_FUNCS(crypt_r)
 AC_CHECK_FUNCS(daemon)
 AC_CHECK_FUNCS(dirfd)
 AC_CHECK_FUNCS(dl_iterate_phdr)