Function calls overhead

[Richard (Rikki) Andrew Cattermole]

Performance of builds that are not optimized by ldc or gdc are 
irrelevant to concerns on performance.

These builds will always be slow, additional overhead of some hooks are 
the least of it.

Usually for such builds the concern is more for debuggability, so 
keeping them as separate symbols is to the benefit of the user, rather 
than an issue.