Trimmed from diffing upstream d0de5ee5276e83ac1b5ff6bde56084a565bff5fb
to 3c8ecfe9bc8a7fbee58425be69aea89ae3f718e9, which included some
extraneous bits.

--- a/configure.ac
+++ b/configure.ac
@@ -35,7 +35,7 @@ AS_HELP_STRING([--disable-netrc],[enable .netrc support]),,
 
 NEON_WITH_LIBS
 
-NE_REQUIRE_VERSIONS([0], [27 28 29 30 31 32])
+NE_REQUIRE_VERSIONS([0], [27 28 29 30 31 32 33])
 
 dnl Don't enable zlib or ACL support in neon
 NEON_WITHOUT_ZLIB