[tlbuild] asy-2.58 build?

[Karl Berry]

I committed the asymptote-2.58 sources to TeX Live. John says this
release should be stable and has many enhancements over what we released
with the original TL19. So if everyone is up for trying to compile it,
and it succeeds, it seems like it would be worth updating now instead of
waiting until next year. Due to the coupled nature of the support files
and binaries, we have to update all platforms if we update any.

So, please give it a whirl if you can.

If you don't have the glm headers, Dick wrote:

    The new version uses glm, which is available from
    https://glm.g-truc.net/0.9.9/index.html. This is just a set of
    headers, so after uncompressing to a folder named glm, we must reach
    inside to find a new folder also named glm, and move this folder to
    "includes".

(I haven't updated the build web page with this info yet. Refinements
welcome. :) --thanks, karl.