Add ninja-build to full.

[gengjiawen]

It's a very popular tools, used to build V8 and Node.js. Very essential to c/cpp devs. Also it's very small, around 100kb.

[jankeromnes]

Thanks for the suggestion! That's a good idea.

My only worries would be:

• What size delta would this add to gitpod/workspace-full? (We can assess this by starting a PR and compare the built image with master)

• Do we know for sure that projects will pickup and use our installed Ninja? (It seems to me that many projects now download a custom toolchain as part of their build process, bypassing our installed tools -- for example, I believe Chromium and Firefox both download latest Clang to build, even though Gitpod already has latest Clang installed)

[gengjiawen]

What size delta would this add to gitpod/workspace-full?

Since docker has compression. I would expect like less than 100kb. I will start a PR later :)

I believe Chromium and Firefox both download latest Clang to build

Yeap, they have internal toolchain. But https://github.com/bnoordhuis/v8-cmake can benefit from this.
Also, we start using Node.js ninja build in CI, see nodejs/node#37499.