04e485273b
BuildDescForRelation() main job is to convert ColumnDef lists to pg_attribute/tuple descriptor arrays, which is really mostly an internal subroutine of DefineRelation() and some related functions, which is more the remit of tablecmds.c and doesn't have much to do with the basic tuple descriptor interfaces in tupdesc.c. This is also supported by observing the header includes we can remove in tupdesc.c. By moving it over, we can also (in the future) make BuildDescForRelation() use more internals of tablecmds.c that are not sensible to be exposed in tupdesc.c. Discussion: https://www.postgresql.org/message-id/flat/52a125e4-ff9a-95f5-9f61-b87cf447e4da@eisentraut.org