(Option 1) Cause win32.mak to print error when HOST_DC is not set

[marler8997]

I spent way too much time on this one. The limitations of Digital Mars' make program made this one quite difficult, this is the best mechanism I could come up with to cause the make file to fail with a nice error messages when HOST_DC is not set.

[dlang-bot]

Thanks for your pull request, @marler8997! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.

Some tips to help speed things up:

• smaller, focused PRs are easier to review than big ones

• try not to mix up refactoring or style changes with bug fixes or feature enhancements

• provide helpful commit messages explaining the rationale behind each change

Bear in mind that large or tricky changes may require multiple rounds of review and revision.

Please see CONTRIBUTING.md for more information.

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

[JinShil]

See also #7256

[marler8997]

Had to make another change, it appears to be another bug in digital mars make, I had to split the debdmd and reldmd targets into one with their dependencies and one with their rules/actions. If both the dependencies and actions are in the same staement, then make will not execute the actions.

[andralex]

I'm unclear about how this works. I'd expect it would be simpler, what's with all the additional work? What does "deb" and "rel" mean? I assume "debug" and "release"? It was confusing as heck because "deb" also stands in for "debian".

[andralex]

This has never worked well for me. I have no idea how it works for other people. Apparently the approach has issues: https://stackoverflow.com/questions/4440500/depending-on-directories-in-make

[marler8997]

I believe the stack overflow question you submitted is an issue with GNU make. This makefile uses Digital Mars make and I haven't seen an issue with how it handles directory dependencies.

[wilzbach]

@andralex as I have stated on other pull requests in the past: depending on directories works only if you use them as order-only dependencies.
Anyhow DigitalMars Make so different from Make, that it shouldn't be called Make 😉

[marler8997]

I'd expect it to be simpler as well, but this was the simplest I could figure out how to do. I believe my changes along with the existing complexity in the Makefile is due to limitations and bugs in Digital Mars make.

[JinShil]

What does "deb" and "rel" mean?

Indeed. Please spell things out.

[marler8997]

debdmd and reldmd are public targets apart of the public interface of the Makefile. I'm not against changing them but I would consider those changes outside of the scope of this PR. This PR only addresses proper error handling of the HOST_DC environment variable.

[wilzbach]

I prefer this approach over Option 2, it's a bit more DRY.

[wilzbach]

Why is this line needed?

[marler8997]

I assume you are asking why have the extra target, why not do this:

debdmd: check-host-dc 
    $(DMDMAKE) "OPT=" "DEBUG=-D -g -DUNITTEST" "DDEBUG=-debug -g -unittest" "DOPT=" "LFLAGS=-L/ma/co/la" $(TARGETEXE)

Instead of this:

debdmd: check-host-dc debdmd-make

debdmd-make:
    $(DMDMAKE) "OPT=" "DEBUG=-D -g -DUNITTEST" "DDEBUG=-debug -g -unittest" "DOPT=" "LFLAGS=-L/ma/co/la" $(TARGETEXE)

The answer is because it doesn't work :) I don't know why, my guess is it's a bug in Digital Mars Make, but if you combine them into 1 statement, then make ignores the commands.

[wilzbach]

Oh I was trying to politely ask you to remove the debugging output ;-)
I understand that DigitalMars Make is "rather rudimentary" ...