Feature request: make it easier to choose which AMIs to build

[woodhull]

We need to maintain a fork of the stack to support encrypted disks for our agent machines and a few other tweaks to the default stack environment.

We only need the linux-x86 AMIs for our stack, but there is no way to easily skip the other architechtures while building the stack. An env variable passed to make build would help us skip this work.

This is not really a problem except that building the images takes a very long time to run, especially the windows ones. It makes rebuilding the stack after making tweaks very tedious.

[keithduncan]

I agree this would be a good feature to add to the Makefile @woodhull, it’s not something I’ll have time to look into in the short term but would absolutely welcome a pull request that makes this change in a backwards compatible way 😄