ed: add support for -p command-line option as mandated by POSIX

The POSIX.1-2008 specification of ed(1) mandates two command-line
options: -p (for specifying a prompt string) and -s (to suppress writing
of byte counts). This commit adds support for the former. Furthermore,
it also changes the default prompt string to an empty string (instead
of ": ") since this is also mandated by POSIX:

	-p string Use string as the prompt string when in command mode.
	          By default, there shall be no prompt string.

function                                             old     new   delta
ed_main                                              112     144     +32
packed_usage                                       34074   34097     +23
doCommands                                          1889    1887      -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 55/-2)              Total: 53 bytes

Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions