ffc_sv_create: zero just the length

The array shouldn't need to be zero-initialized.
We should never read from any element of the array
that has not been initialized by a push or extend

Author: kolemannix

ffc.h

@@ -1640,7 +1640,8 @@ bool ffc_sv_try_extend(ffc_sv* sv, ffc_bigint_limb_span s) {
 // create from existing limb span.
 ffc_internal ffc_inline
 ffc_sv ffc_sv_create(ffc_bigint_limb_span s) {
-  ffc_sv new_one = {0};
+  ffc_sv new_one;
+  new_one.len = 0;
   ffc_sv_try_extend(&new_one, s);
   return new_one;
 }

src/bigint.h

@@ -77,7 +77,8 @@ bool ffc_sv_try_extend(ffc_sv* sv, ffc_bigint_limb_span s) {
 // create from existing limb span.
 ffc_internal ffc_inline
 ffc_sv ffc_sv_create(ffc_bigint_limb_span s) {
-  ffc_sv new_one = {0};
+  ffc_sv new_one;
+  new_one.len = 0;
   ffc_sv_try_extend(&new_one, s);
   return new_one;
 }