Thank you to Rainer: shared library support

[Richard Andrew Cattermole (Rikki)]

A big shout-out to Rainer for improving dmd's shared library 
support and getting [0] merged!


While druntime support has yet to be implemented, this is a major 
stepping stone to improving shared library support in all D 
compilers so that common scenarios will not cause linker errors 
as they do now.


So thank you Rainer for helping to solve this long standing issue.


To Walter: any chance for an implementation of DIP-Export2? That 
way for next release we could have a preview of what D's shared 
library support will look like and be mostly hashed out!

[0] https://github.com/dlang/dmd/pull/14849