diff --git a/configure.ac b/configure.ac
index 82b5ac6f53cff4125a370eaf4ad01c00a728b410..c5bd007f42c60266fb1a86b2905640a76ebc8cd9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -125,8 +125,9 @@ AC_TYPE_SIZE_T
 AC_HEADER_TIME
 
 # Needed by the supplied memcmp.c
-AC_C_BIGENDIAN
+LSH_FUNC_ALLOCA
 
+AC_C_BIGENDIAN
 AC_REPLACE_FUNCS(memxor)
 
 LSH_GCC_ATTRIBUTES