diff --git a/lib/cpp/configure.ac b/lib/cpp/configure.ac
index ee9995e..b854ebd 100644
--- a/lib/cpp/configure.ac
+++ b/lib/cpp/configure.ac
@@ -14,6 +14,10 @@
 
 AC_CHECK_FUNCS([socket])
 
+AC_CHECK_FUNCS([strtol])
+
+AC_CHECK_FUNCS([strtoul])
+
 AC_CHECK_HEADERS([arpa/inet.h])
 
 AC_CHECK_HEADERS([inttypes.h])
@@ -52,6 +56,8 @@
 
 AC_TYPE_SIZE_T
 
+AC_TYPE_INT16_T
+
 AC_TYPE_INT32_T
 
 AC_TYPE_INT64_T