message: add documentation for build scripts
diff: @@ -96,6 +96,7 @@ the following:
  package manager will be installed.
  # Clone the package manager to the specific Git commit.
  # Apply patches to package manager. For example, disabling extra config scopes in Spack.
  +# Copy project specific package recipes over the packages manager's recipes.
  # Clean previous temporary information from previous runs that may bleed into this run.
  # Optionally create a package source mirror.
  # Install packages via the selected package manager.
  @@ -106,6 +107,25 @@ the following:
  * `Uberenv's Github repo <https://github.com/LLNL/uberenv>`_
  * `Uberenv's documentation <https://uberenv.readthedocs.io/en/latest/>`_
  +Level 3: Build Scripts
  +----------------------
  +
  +There are three "build" scripts that live in `scripts/llnl` that are designed
  +to handle suites of building TPLs via uberenv and Spack. They automatically
  +handle the platform differences and know the full list of compilers and package
  +specs required.
  +
  +* `scripts/spack/specs.json`: This contains a list of all specs required per platform
  + or machine name.
  +* `build_tpls.py`: This script starts with building all TPLs listed in `specs.json`.
  + It will copy the generated host-configs to the base of the Axom repository.
  + After building all of the TPLs, it will test Axom against those built TPLs. As well,
  + as testing the installed `using-with-cmake` example for correctness.
  +* `build_src.py`: This scripts takes the existing host-configs, or the specific one you point
  + at, and builds and tests Axom against them. It also tests the `using-with-cmake` examples.
  +* `build_devtools.py`: This script builds and installs the developer tools listed in the `axomdevtools`
  + Spack package. It also uses a different set of Spack configs located in `scripts/spack/devtools_config`,
  + so that the regular Spack configs can reuse the seldom and previously built developer tools.
  =============
  Updating TPLs
  