Allow configuring meson, make and pkgconfig versions via bzlmod exten…

[jsharpe]

…sion

[jsharpe]

@jheaff1 any ideas how I could avoid this hardcoded version number?
I want the end user to not have to do use_repo(tools, "meson_src") if they're using this macro which they currently have to; maybe we should make the toolchain variants have to be declared via a module extension and then generate this toolchain into the toolchain_hub e.g.

tools.meson(version = "1.1.1")
tools.meson(version = "1.1.1", requirements = ["@pypi__numpy"])

?

[jsharpe]

@jheaff1 @UebelAndre One part of this I'm yet to design is what the module extension should look like for selecting between preinstalled tools and prebuilt / built from source tools. Any ideas?

The extension API currently looks like this:

tools.cmake(version = "3.29.1")
tools.ninja(version = "1.12.0")

we could do something like:

tools.cmake(version = "3.29.1", allow_build_from_source = False)
tools.ninja(version = "1.11.1", use_prebuilt_binaries = False)
tools.pkgconfig(preinstalled_version = True)

but very much open to ideas on this.