- fix segfault in nameif with mactab file
  (by fixing and shrink config parser)

function                                             old     new   delta
config_free_data                                       -      37     +37
config_open                                           43      48      +5
pack_gzip                                           1658    1660      +2
nameif_main                                          527     525      -2
SynchronizeFile                                      629     623      -6
make_device                                         1184    1176      -8
config_close                                          31      18     -13
config_read                                          431     393     -38
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/5 up/down: 44/-67)            Total: -23 bytes

diff --git a/include/libbb.h b/include/libbb.h
index c124b1a..aafdfa3 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -995,7 +995,7 @@
 	char *line, *data;
 	int lineno;
 } parser_t;
-FILE* config_open(parser_t *parser, const char *filename) FAST_FUNC;
+parser_t* config_open(const char *filename) FAST_FUNC;
 /* TODO: add define magic to collapse ntokens/mintokens/comment into one int param */
 int config_read(parser_t *parser, char **tokens, int ntokens, int mintokens, const char *delims, char comment) FAST_FUNC;
 void config_close(parser_t *parser) FAST_FUNC;