libbb: new function bb_die_memory_exhausted

libbb: new function bb_die_memory_exhausted

function                                             old     new   delta
bb_die_memory_exhausted                                -      10     +10
xstrdup                                               28      23      -5
xsetenv                                               27      22      -5
xrealloc                                              32      27      -5
xputenv                                               22      17      -5
xmalloc                                               30      25      -5
xfdopen_helper                                        40      35      -5
xasprintf                                             44      39      -5
wget_main                                           2387    2382      -5
open_socket                                           54      49      -5
glob_brace                                           419     414      -5
bb_get_chunk_from_file                               146     141      -5
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/11 up/down: 10/-55)           Total: -45 bytes

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