diff --git a/configure.ac b/configure.ac
index cd43532..16dc051 100644
--- a/configure.ac
+++ b/configure.ac
@@ -17,6 +17,7 @@ AC_CONFIG_SRCDIR([softflowd.c])
 
 AC_CONFIG_HEADER(config.h)
 AC_PROG_CC
+AC_PROG_CC_STDC
 AC_PROG_INSTALL
 
 # Optional verbose warnings for gcc, see below