Manual conversion of Baserock's build-essential stratum

This huge commit is a manual conversion, notes on what was
needed:

  o project.conf defines the arch specific stuff which was
    previously hardcoded into YBD, so the stage1 target and target
    etc are all defined by the build-essential project.conf

  o Direct and easy changes for git source representation

  o Added stage1.bst & stage2.bst "stacks", everything built in
    stage2 build-depends on stage1.bst, and the final build-essential
    products build-depend on stage2.bst (note build-depend means
    to depend _only_ for building, not propagated forward).

  o Instead of using host tools we build on the GNOME flatpak
    sdk/platform bundles

  o Some build-essential morph files use $(dirname $(pwd)) for a sysroot,
    which is weird, it means the morph files rely on building at one directory
    below the slash sysroot - in buildstream we build in /buildstream/build
    which is two - had to replace these with $(dirname $(dirname $(pwd))) instead

  o Remove the devices sections from the fhs-dirs elements, not allowed
    to create static device nodes in buildstream.

1 files changed, 33 insertions, 0 deletions

diff --git a/build-essential/stage2-reset-specs.bst b/build-essential/stage2-reset-specs.bst
new file mode 100644
index 00000000..4b3b6f91
--- /dev/null
+++ b/build-essential/stage2-reset-specs.bst
@@ -0,0 +1,33 @@
+kind: manual
+
+depends:
+- filename: build-essential/stage1.bst
+  type: build
+- build-essential/stage2-linux-api-headers.bst
+- build-essential/stage2-glibc.bst
+
+variables:
+  prefix: /tools
+
+environment:
+  PATH: /tools/bin:/usr/bin:/bin:/usr/sbin:/sbin
+
+config:
+  # Nasty hack to get around being unable to reliably add configuration to gcc,
+  # hence the gcc specs are modified, combined with Baserock's rootfs protection
+  # preventing specs being modified before builds.
+  # The limitation is overcome by installing files as part of a chunk, which
+  # overwrites previous files.
+  # New specs were added for the bootstrap builds, but after stage2 we start
+  # having chrooted builds, so the old specs need to be replaced.
+  # Unfortunately we can't just replace the specs with the ones gcc produces,
+  # since gcc behaves differently without specs to with specs it produces!
+  # So we use a **NASTY HACK** to replace the specs symlink with one that
+  # points to a file that doesn't exist.
+  install-commands:
+  - |
+    STAGE2_SYSROOT="$(dirname $(dirname $(pwd)))"
+    specs_dir="$(dirname $(%{target-stage1}-gcc -print-libgcc-file-name))"
+    target_specs_dir="%{install-root}/${specs_dir#$STAGE2_SYSROOT}"
+    mkdir -p "$target_specs_dir"
+    ln -s "temporary specs removed by baserock bootstrap" "$target_specs_dir/specs"