Detection of U8T_DECOMPOSE seems to be broken when cross-compiling,
so needs to be preseeded.

-snip-
checking for utf8_mime2text signature... new
checking for U8T_DECOMPOSE...
configure: error: utf8_mime2text() has new signature, but U8T_CANONICAL
 is missing. This should not happen. Check config.log for additional information.
-snap-

This requires also a patch for PHP to make the preseeding working.

Signed-off-by: Michael Heimpold <mhei@heimpold.de>