diff --git a/lib/cpp/configure.ac b/lib/cpp/configure.ac
index 1f2763c..878e55a 100644
--- a/lib/cpp/configure.ac
+++ b/lib/cpp/configure.ac
@@ -28,6 +28,12 @@
 
 AC_CHECK_FUNCS([strtoul])
 
+AC_CHECK_FUNCS([memmove])
+
+AC_CHECK_FUNCS([strstr])
+
+AC_CHECK_FUNCS([strchr])
+
 AC_CHECK_HEADERS([arpa/inet.h])
 
 AC_CHECK_HEADERS([fcntl.h])
@@ -100,8 +106,4 @@
 
 AC_PROG_LIBTOOL
 
-CFLAGS="-g -O2"
-
-CXXFLAGS="-g -O2"
-
 AC_OUTPUT(Makefile)