ldc2 --version: "built with D compiler version"

[Johan Engelen via digitalmars-d-ldc]

Hi all,
  I just added information about which D compiler was used to 
build LDC to `ldc2 --version`. I think it is important 
information, at least for now when there may be some hidden 
differences/bugs between different D compilers.

It looks like this now:
❯ bin/ldc2 --version
LDC - the LLVM D compiler (febfca):
   based on DMD v2.069.2 and LLVM 3.9.0svn-r263048
   built with DMD64 D Compiler v2.070.2
   Default target: x86_64-apple-darwin15.3.0
   Host CPU: haswell
   http://dlang.org - http://wiki.dlang.org/LDC

cheers,
   Johan