Remove option DWITH_READLINE, because readline is no longer bundled
http://dev.mysql.com/doc/refman/5.6/en/source-configuration-options.html#option_cmake_with_readline
--- a/databases/mysql56-client/Makefile.common
+++ b/databases/mysql56-client/Makefile.common
@@ -63,7 +63,6 @@ CMAKE_ARGS+= -DMYSQL_DATADIR=${MYSQL_DATADIR}
# always use our own readline, not MySQL bundled one
CMAKE_ARGS+= -DWITH_LIBEDIT=OFF
-CMAKE_ARGS+= -DWITH_READLINE=OFF
CMAKE_ARGS+= -DWITH_ZLIB="system"
CMAKE_ARGS+= -DDEFAULT_CHARSET=${MYSQL_CHARSET:Q}
CMAKE_ARGS+= -DDEFAULT_COLLATION=${MYSQL_COLLATION:Q}