diff --git a/configure.in b/configure.in
index 89819e0c9..c44c06dd1 100644
--- a/configure.in
+++ b/configure.in
@@ -148,8 +148,8 @@ fi
 AC_CHECK_FUNCS(_getpty asnprintf asprintf gethostname getmsg)
 AC_CHECK_FUNCS(grantpt logwtmp mktime ptsname rand random revoke)
 AC_CHECK_FUNCS(select setitimer setlogin setpcred setpgid setsid)
-AC_CHECK_FUNCS(setsid setsockopt strstr timegm ttyname unlockpt)
-AC_CHECK_FUNCS(vasnprintf vasprintf vhangup)
+AC_CHECK_FUNCS(setsid setsockopt strstr timegm ttyname umask)
+AC_CHECK_FUNCS(unlockpt vasnprintf vasprintf vhangup)
 
 AC_TYPE_SIGNAL
 if test "$ac_cv_type_signal" = "void" ; then