This replaces previous -S, --search-regex option. The regex option
can now be used in the ownedby and search modes.
Also added -S, --show option which is the default mode if no other
mode set, and defaults to it to preserve compatibility.
To put a package on hold mode:
$ xbps-pkgdb -m hold foo
To unhold the package:
$ xbps-pkgdb -m unhold foo
To list packages on hold mode:
$ xbps-query -H
This also close#12 from github.
This routine will spawn a thread per core to process N items stored
in the specified array, the last thread gets the remainder of items left.
Results have shown that xbps benefits if there is a considerable amount
of items and number of threads being spawned.
Use it in xbps_pkgdb_foreach_cb(), xbps-pkgdb(8), xbps-query(8)
and xbps-rindex(8).
On UP systems there's no overhead because pthread(3) is not used at all.
WIP! investigate if it can be used in libxbps (xbps_rpool_foreach()),
and finish conversion of xbps-rindex(8) -c.
The list of required external deps is now confuse, libarchive and openssl.
libxbps now includes a wrapper for proplib prefixed with xbps_ rather than prop_.
