bc: remove unnecessary initializations

function                                             old     new   delta
zdc_program_asciify                                  403     395      -8
zbc_program_print                                    691     683      -8
zbc_program_exec                                    4079    4068     -11
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-27)             Total: -27 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/miscutils/bc.c b/miscutils/bc.c
index 58e3bcb..cf620f8 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -5058,6 +5058,7 @@
 	return bc_vec_item(v, ptr->idx);
 }
 
+// 'num' need not be initialized on entry
 static BC_STATUS zbc_program_num(BcResult *r, BcNum **num, bool hex)
 {
 	switch (r->t) {
@@ -5082,12 +5083,10 @@
 			hex = hex && len == 1;
 			base_t = hex ? 16 : G.prog.ib_t;
 			s = zbc_num_parse(&r->d.n, str, base_t);
-
 			if (s) {
 				bc_num_free(&r->d.n);
 				RETURN_STATUS(s);
 			}
-
 			*num = &r->d.n;
 			r->t = BC_RESULT_TEMP;
 			break;
@@ -5566,7 +5565,6 @@
 		RETURN_STATUS(bc_error_stack_has_too_few_elements());
 
 	r = bc_vec_item_rev(&G.prog.results, idx);
-	num = NULL; // is this NULL necessary?
 	s = zbc_program_num(r, &num, false);
 	if (s) RETURN_STATUS(s);
 
@@ -6203,7 +6201,6 @@
 		RETURN_STATUS(bc_error_stack_has_too_few_elements());
 	r = bc_vec_top(&G.prog.results);
 
-	num = NULL; // TODO: is this NULL needed?
 	s = zbc_program_num(r, &num, false);
 	if (s) RETURN_STATUS(s);
 
@@ -6268,7 +6265,6 @@
 		RETURN_STATUS(bc_error_stack_has_too_few_elements());
 	r = bc_vec_top(&G.prog.results);
 
-	n = NULL; // is this needed?
 	s = zbc_program_num(r, &n, false);
 	if (s) RETURN_STATUS(s);