allow on stack with betterC

[test]

On Tuesday, 23 October 2018 at 11:17:03 UTC, Dennis wrote:
> On Tuesday, 23 October 2018 at 10:18:56 UTC, test wrote:
>> I can not user static array because the length is a runtime 
>> vars.
> When compiling with dmd and -betterC I got a linker error 
> "undefined reference to '__alloca'", but with LDC it worked 
> fine.



Thanks,  alloca is what i am look for.


to @Tony

when you use "scope tmp = new ubyte[4]", it is much fast then 
malloc because it is on stack.