bc: print error line numbers

bc: print error line numbers

FILE:
	print 1
	print "

$ busybox bc -q FILE
bc: FILE:2: string end could not be found
ready for more input
>>> _

function                                             old     new   delta
bc_verror_msg                                          -      99     +99
bc_lex_file                                           12      28     +16
bc_lex_next                                           77      92     +15
dc_lex_token                                         687     701     +14
bc_lex_token                                        1237    1251     +14
bc_posix_error_fmt                                    90      58     -32
bc_error_fmt                                          70      36     -34
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/2 up/down: 158/-66)            Total: 92 bytes
   text	   data	    bss	    dec	    hex	filename
 987108	    485	   7296	 994889	  f2e49	busybox_old
 987210	    485	   7296	 994991	  f2eaf	busybox_unstripped

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