hush: export PWD

function                                             old     new   delta
set_pwd_var                                            -      36     +36
hush_main                                            941     951     +10
evalvar                                             1365    1363      -2
ash_main                                            1364    1362      -2
builtin_cd                                            75      72      -3
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/3 up/down: 46/-7)              Total: 39 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash.c b/shell/ash.c
index 35d5cde..eca4ab9 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -12985,7 +12985,7 @@
 	/* from var.c: */
 	{
 		char **envp;
-		char ppid[sizeof(int)*3 + 1];
+		char ppid[sizeof(int)*3 + 2];
 		const char *p;
 		struct stat st1, st2;
 
@@ -12996,7 +12996,7 @@
 			}
 		}
 
-		snprintf(ppid, sizeof(ppid), "%u", (unsigned) getppid());
+		sprintf(ppid, "%u", (unsigned) getppid());
 		setvar("PPID", ppid, 0);
 
 		p = lookupvar("PWD");