fn reallocarray(opt_base: ?[*]align(alignment_bytes) u8, elems: usize, len: usize) callconv(.c) ?[*]align(alignment_bytes) u8
fn reallocarray(opt_base: ?[*]align(alignment_bytes) u8, elems: usize, len: usize) callconv(.c) ?[*]align(alignment_bytes) u8 { const n = std.math.mul(usize, elems, len) catch return nomem(); return realloc(opt_base, n); }