MFC revisions 253175, 268999, 269027, 269351-269352, 269354, 269460,
270283, 270505, 270954, 270989, 273067, and 273068:
r253175: Introduce f_which() to common.subr
r268999: Add new bsdconfig example scripts; remove obsolete ones
r269027: Update bsdconfig dot module; fixes and enhancements
r269351: Add setvar() for non-FreeBSD platforms using bash as /bin/sh
r269352: Fix syntax error when run under bash
r269354: Update setvar() function introduced in r269351
r269460: Update f_xdialog_info() in bsdconfig's dialog.subr include
r270283: Add `-A' flag to pkg-install(8) when installing dependencies
r270505: Optimize f_which() to be slightly faster still (common.subr)
r270954: Update f_dialog_init() for safer getopts usage (dialog.subr)
r270989: Fix for previously mentioned r270954
r273067: Fix awk(1) asorti() implementation to work when called in a loop
r273068: Rename awk(1) asorti() to prevent conflict with GNU awk(1)