ci: Address tight disk space on GHA runners

- Mount the host's root under /host/root so it's visible in the
  containers.
- Remove stuff we don't need to free lots of disk space.
- While we're at it, arrange for the commands (copied from OSL) that
  allow the containers to see a CPU, when available.

Signed-off-by: Larry Gritz <[email protected]>

Author: lgritz

.github/workflows/build-steps.yml

@@ -95,6 +95,10 @@ jobs:
     container:
       image: ${{ inputs.container }}
       volumes: ${{ fromJson( inputs.container_volumes ) }}
+      options: -v /:/host/root ${{ (contains(inputs.runner, 'gpu') && '-e NVIDIA_DRIVER_CAPABILITIES=compute,graphics,utility --gpus all') || '-e A=x' }}
+      # Extra options:
+      # - Ensure the GPU runners have OptiX is visible in the container.
+      # - Mount the native filesystem under /host/root
     env:
       CXX: ${{inputs.cxx_compiler}}
       CC: ${{inputs.cc_compiler}}

src/build-scripts/gh-installdeps.bash

@@ -7,7 +7,16 @@
 
 
 set -ex
-df -h
+
+# Make extra space on the runners
+if [[ -e /host/root ]] ; then
+    df -h .
+    : ${CRUFT_TO_REMOVE:="/host/root/usr/share/dotnet /host/root/usr/local/lib/android /host/root/usr/local/.ghcup"}
+    time rm -rf $CRUFT_TO_REMOVE &
+    sleep 3
+    # rather than block, delete in background, but give it a few secs to start
+    # clearing things out before moving on.
+fi
 
 
 #
@@ -219,7 +228,7 @@ if [[ "$USE_ICC" != "" ]] ; then
     export CC=icc
 fi
 
-df -h
+df -h .
 
 # Save the env for use by other stages
 src/build-scripts/save-env.bash