Since we're skipping Meson's dependency tracking, for the
internal-api-docs custom target, we should just consider it a phony
target and build it on every request.
Change-Id: I3b0bcea30ee9a4830023ccc5bededf995e96cccc
This commit adds the capability for building the Doxygen internal API
docs in the Meson buildsystem, and also makes doing so the default for
the internal-api-docs hydra job. Aside from the /nix-support directory,
which differed only by the hash part of a store path, the outputs of
hydraJobs.internal-api-docs before and after this commit were
bit-for-bit identical on my machine.
Change-Id: I98f0017891c25b06866c15f7652fe74f706ec8e1
