swaponoff: shrink

function                                             old     new   delta
.rodata                                           148469  148468      -1
swap_on_off_main                                     381     379      -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-3)               Total: -3 bytes
   text	   data	    bss	    dec	    hex	filename
 803030	   4090	   9504	 816624	  c75f0	busybox_old
 803027	   4090	   9504	 816621	  c75ed	busybox_unstripped
ash: Use setvar2 some more

(add/remove: 0/0 grow/shrink: 10/15 up/down: 13/-27)          Total: -14 bytes

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