diff --git a/configure.ac b/configure.ac
index 8199f13dc..241062c23 100644
--- a/configure.ac
+++ b/configure.ac
@@ -918,7 +918,8 @@ dnl Checks for library functions.
 dnl AC_PROG_GCC_TRADITIONAL
 AC_TYPE_SIGNAL
 dnl AC_FUNC_VPRINTF
-AC_CHECK_FUNCS( socket \
+AC_CHECK_FUNCS( strtoll \
+                socket \
                 select \
                 strdup \
                 strstr \