LDC: Speed up incremental builds with object file caching

[Johan Engelen via Digitalmars-d-announce]

I just finished another post about LDC:
https://johanengelen.github.io/ldc/2016/09/17/LDC-object-file-caching.html

Thanks in advance for letting me know about any bugs you find, in 
the text or in the code :)

-Johan