Changed find command to build MANIFEST
Changed find command to build MANIFEST

Replaced the -printf option to find with a pipe to sed to support
OS X find where -printf isn't a supported option, frettled++

Signed-off-by: pmichaud <0a197dbb67d5ae8da961dfe1296bbf2dd411b3c6@pobox.com>

rakudo/star,stmuk/star,hoelzro/rakudo-star