betterC and CTFE

[Walter Bright]

BetterC code does not have a GC, and so doesn't allow using the GC. But many 
have correctly pointed out that not having a GC cripples CTFE. CTFE should be 
able to use the GC, it's a major advantage of having a GC (and cripples 
languages with CTFE that don't have GC).

So, making some experiments, I found it usually worked. Searching bugzilla, I 
found one case that didn't:

   https://issues.dlang.org/show_bug.cgi?id=20101

and fixed it:

   https://github.com/dlang/dmd/pull/14789

For those that still suffer the slings and arrows from this problem, please let 
me know the bugzilla issues for them.

P.S. This also applies to @nogc code - CTFE should still be able to use the GC. 
Isn't that cool? Destroy the question "what good a GC is in a systems 
programming language!"