ash: Set SHLVL in ASH_BASH_COMPAT

function                                             old     new   delta
ash_main                                            1456    1505     +49
.rodata                                           148488  148494      +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 55/0)               Total: 55 bytes

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

shell/ash.c

@@ -13012,7 +13012,10 @@ init(void)
 		}
 
 		setvar2("PPID", utoa(getppid()));
-
+#if ENABLE_ASH_BASH_COMPAT
+		p = lookupvar("SHLVL");
+		setvar2("SHLVL", utoa(p ? atoi(p) + 1 : 1));
+#endif
 		p = lookupvar("PWD");
 		if (p) {
 			if (*p != '/' || stat(p, &st1) || stat(".", &st2)