creating conanvcvars file for toolchains

[memsharded]

Changelog: Feature: Use conancvvars.bat file for Meson toolchain
Docs: Omit

[SSE4]

code is repeating 3 times, maybe move it inside self._run instead?

[memsharded]

self._run might use different locations of environment scripts, depending if they are from Conan or from user ones.

[SSE4]

and how do we know this locations?

[memsharded]

If it is a generated file, it will be by definition in the install_folder.
If it is a user file, the user will specify its location.

[SSE4]

but right now it uses self._conanfile.install_folder always, so these 2 lines are repeated.

[memsharded]

but if we put it inside self._run, it will try to apply it to all the environment scripts, which is incorrect

[SSE4]

I mean doing:

    def _run(self, cmd):
       vcvars = os.path.join(self._conanfile.install_folder, "conanvcvars")
        self._conanfile.run(cmd, env=["conanbuildenv", vcvars])

are there other environment scripts in meson toolchain? I can't spot any right now

[memsharded]

Oh, I see what you mean, I was confusing it with self._conanfile.run(). I put some TODOs and some comments there regarding the install or test that I didn't know if they really need the vcvars environment at all. If they need it, then I guess it is ok, if not, each method should define its own environment.

[SSE4]

not sure, probably best add vcvars everywhere, just in case install needs tools from vcvars (e.g. dumpbin or whatever)

[memsharded]

In any case, it is a small detail, can be refactored later, I am merging this, I prefer to have this in the next release.

[SSE4]

are we sure install_folder is always available? I remember it was missing for some cases, e.g. test_package and magic root package