* buildsym.c: Break out initial malloc sizes.

* buildsym.c:  Break out initial malloc sizes.
(record_line):  Record directly in a subfile.  Alloc on demand.
(compare_line_numbers):  Add from xcoffread.c.
(end_symtab):  New params say whether to sort pendings and
linetable.  Patch block stabs if defined.  Shrink linetable before
allocating the symtab.
* buildsym.h:  Delete line_vector* and prev_line_number.  Add
global_stabs and file_stabs for xcoffread.
* dbxread.c (start_subfile):  Move to buildsym.  Change above calls.
* symtab.h:  LINETABLE(symtab) can now be null.  Zap LINELIST.
* symmisc.c, symtab.c:  Cope with null LINETABLEs.