C99 stdbool turned 18 this year. There really is no reason to use our
own, except in the library interface for backward
compatibility. Convert the cli and test binaries to stdbool.
The 'insert' command will be better served if parse_tag_command_line
modifies a pre-populated list (of new.tags) instead of clobbering the
list outright. The sole existing caller, notmuch_tag_command, is
unaffected by this change.
Command line parsing is factored out into a function
parse_tag_command_line in tag-util.c.
There is some duplicated code eliminated in tag_query, and a bunch of
translation from using the bare tag_op structs to using that tag-utils
API.
The memory usage discipline of tag_op_list_t is never to free the
internal array of tag operations before freeing the whole list, so it
makes sense to take advantage of hierarchical de-allocation by talloc.
By not relying on the context passed into tag_parse_line, we can allow
tag_op_list_t structures to live longer than that context.
These are meant to be shared between notmuch-tag and notmuch-restore.
The bulk of the routines implement a "tag operation list" abstract
data type act as a structured representation of a set of tag
operations (typically coming from a single tag command or line of
input).
