hush: use ash's read builtin

function                                             old     new   delta
shell_builtin_read                                     -    1000   +1000
set_local_var_from_halves                              -      24     +24
setvar2                                                -       7      +7
...
popstring                                            140     134      -6
ash_main                                            1375    1368      -7
setvar                                               184     174     -10
arith_set_local_var                                   36       -     -36
builtin_read                                        1096     185    -911
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 5/23 up/down: 1038/-1007)        Total: 31 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/match.h b/shell/match.h
index 98ff874..c022ceb 100644
--- a/shell/match.h
+++ b/shell/match.h
@@ -5,6 +5,8 @@
 
 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
+//TODO! Why ash.c still uses internal version?!
+
 typedef char *(*scan_t)(char *string, char *match, bool match_at_left);
 
 char *scanleft(char *string, char *match, bool match_at_left);