DMD front end should define a version containing the front end version

[SiegeLord]

I am quite sick of DMDFE breaking my code every release with bugs
that are then solved for the next release (that is, if they are
solved). If I track the latest compiler, then my code is broken
for older compilers (and you are kidding yourselves if you think
people always use the latest DMDFE/DMDFE from git). I want DMDFE
to define a version identifier so I can provide version specific
workarounds and/or disable features so that my code at least
compiles for each DMDFE.

__traits(compiles,) is not sufficient, as some bugs that are
crippling my code right now are ICE's.

Detecting the compiler version during the build process is not
sufficient, as I'd have to force my build process onto everybody
who uses my code.

The only way to do this right now, I think, is to look for added
features (because every DMDFE keeps adding features... soon we'll
have all the features)... but this is awkward.

Seriously... D compiler development process will not get better
and you will keep adding bugs to it that break people's code. At
least make it easier for people to cope with this nonsense.

I probably can implement this myself, but I'd like some assurance
that it will be merged before I write an enhancement request on
bugzilla and waste time implementing it. Maybe this feature is
already available and I'm not aware of it?