hush: fix "unset PS1/PS2", and put them into initial variable set

"unset PS1/PS2" causes prompts to be empty strings

function                                             old     new   delta
hush_main                                           1031    1089     +58
goto_new_line                                         27      33      +6
fgetc_interactive                                    244     245      +1
unset_local_var                                      155     149      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/1 up/down: 65/-6)              Total: 59 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 678c4d29c..d5e92e84c 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -430,7 +430,8 @@ static void put_till_end_and_adv_cursor(void)
 static void goto_new_line(void)
 {
         put_till_end_and_adv_cursor();
-        if (cmdedit_x != 0)
+        /* "cursor == 0" is only if prompt is "" and user input is empty */
+        if (cursor == 0 || cmdedit_x != 0)
                 bb_putchar('\n');
 }