diff --git a/lib/cpp/configure.ac b/lib/cpp/configure.ac
index 8763a4a..d0fc7c1 100644
--- a/lib/cpp/configure.ac
+++ b/lib/cpp/configure.ac
@@ -48,6 +48,8 @@
 
 AC_CHECK_HEADERS([unistd.h])
 
+AC_C_INLINE
+
 AX_BOOST_BASE([1.33.1])
 
 AX_EVENT_BASE([1.2.0])