(Fmake_indirect_buffer): New function.

(Fmake_indirect_buffer): New function.
(Fbuffer_base_buffer): New function.
(syms_of_buffer): defsubr them.

(reset_buffer): Don't alter intervals here.
(Fget_buffer_create): Use BUF_MARKERS.  Init BUF_INTERVALS here.
(Fkill_buffer): Use BUF_MARKERS; but don't touch it in indir buf.
Likewise BUF_INTERVALS.
(init_buffer_once): Set up .text and BUF_INTERVALS
in buffer_local_symbols and buffer_defaults.

(Fkill_buffer): Don't free the text in indirect buffer.
When killing a base buffer, kill its indirect buffers first.

(set_buffer_temp): New function.

(reset_buffer_local_variables): Initialize buffer_file_type field.

(Fget_buffer_create): Initialize pt_marker, begv/zv_marker.
(set_buffer_internal): Use and update these markers.
Copy undo_list in and out of the base buffer.

(Fget_buffer_create): Init save_modiff field here.
(reset_buffer): Not here.
(Fbuffer_modified_p): Use BUF_SAVE_MODIFF.
(Fset_buffer_modified_p): Use SAVE_MODIFF.
(Fkill_buffer, list_buffers_1): Use BUF_SAVE_MODIFF.

(Fget_buffer_create): Initialize the size and text fields.