diff --git a/configure.in b/configure.in
index a14cde1..e255111 100644
--- a/configure.in
+++ b/configure.in
@@ -31,7 +31,8 @@ dnl Checks for library functions.
 AC_FUNC_MMAP
 AC_FUNC_VPRINTF
 AC_CHECK_FUNCS(gethostname gethostbyname connect gettimeofday getwd mkdir \
-	putenv select socket strerror strstr vsnprintf)
+	putenv select socket strerror strstr snprintf _snprintf vsnprintf \
+	_vsnprintf)
 
 AC_ARG_ENABLE(release,
 [  --enable-release        compile release (with optimization)],