[dmd-internals] What are the references to the DMD source directory in my binaries?

[Rico Huijbers via dmd-internals]

Hi,

I'm trying to build and package my D application using the Nix "purely
functional" package manager (https://nixos.org/nix/).

A LITTLE INTRODUCTION

This package manager determines a unique hash from everything that goes
into a build cycle (build scripts, sources, versions of dependencies, etc)
and builds every derivation into a directory identified by that hash.
Conversely, if a directory with that hash already exists, the package
doesn't need to be built because it's up-to-date, by definition.

Because those hashes are very unlikely to occur by chance, the package
manager crawls all files in the newly built directory for references to
hashes of the input dependencies, and records those as run-time
dependencies.

It's then possible to zip up a single package and all of its transitive run
time dependencies, using the command nix-copy-closure (which for example
includes the exact glibc the application was built against), and deploy it
in a minimal busybox environment, for example.

MY ISSUE

This is all just a big preamble for my question: apparently, DMD leaves
references to the compiler directory in a compiled binary. This causes the
"dependency crawler" process to register DMD, and in turn all of _its_
dependencies, as run-time dependencies of my application, which is adding
~100MB to the size of my package bundle. Which, obviously, should not be
necessary.

I can tell using 'strings' that they're all references to include files:

    vagrant at vagrant-ubuntu-utopic-64:~$ strings webapp | grep dmd

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/format.d-mixin-736

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/format.d

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/format.d

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/uni.d

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/variant.d

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/core/demangle.d

/nix/store/3rj0sxwbp2lfddwya2smvkj4cl7y3lvs-dmd-2.066.1/include/d2/std/variant.d

But other than that, I'm at a loss as to what these strings are for, and
more importantly, how I can get rid of them to cut my run-time dependency
set.

Any ideas?

Thanks.
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