bc: fix inverted POSIXness test, improve messages, commonalize message strings

function                                             old     new   delta
bc_lex_token                                        1251    1285     +34
bc_POSIX_does_not_allow_bool_ops_this_is_bad           -      25     +25
bc_POSIX_does_not_allow_empty_X_expression_in_for      -      20     +20
bc_POSIX_does_not_allow                                -      20     +20
bc_parse_expr                                       2146    2151      +5
bc_num_ulong                                         103      92     -11
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 2/1 up/down: 104/-11)            Total: 93 bytes
   text	   data	    bss	    dec	    hex	filename
 987210	    485	   7296	 994991	  f2eaf	busybox_old
 987084	    485	   7296	 994865	  f2e31	busybox_unstripped
^^^^^^^

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