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, 37 insertions, 0 deletions

diff --git a/build-essential/stage2-gcc-fixed-headers.bst b/build-essential/stage2-gcc-fixed-headers.bst
new file mode 100644
index 00000000..a83fca25
--- /dev/null
+++ b/build-essential/stage2-gcc-fixed-headers.bst
@@ -0,0 +1,37 @@
+kind: manual
+
+sources:
+- kind: git
+  url: upstream:gcc-tarball
+  track: baserock/build-essential
+  ref: b3c9b176c1f10ebeff5700eb3760e9511f23fa06
+
+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:
+  install-commands:
+  # Stage 1 GCC's fixincludes process created a limits.h before there was
+  # a real limits.h available for the target. This step (taken from Linux
+  # Linux From Scratch) creates a better one so that stage 2 GCC can compile.
+  #
+  # THIS IS A FRAGILE HACK! We need to replace the headers. The only way to
+  # overwrite files in a staging area is to install a new chunk.
+  # This is undesired behaviour in the long term, as we want to never
+  # have overlaps, so this functionality may go away.
+  - |
+    libgcc_dir=$(dirname $(%{target-stage1}-gcc -print-libgcc-file-name))
+    sysroot="$(dirname $(dirname $(pwd)))"
+    target_libgcc_dir="${libgcc_dir#$sysroot}"
+    mkdir -p "%{install-root}/$target_libgcc_dir/include-fixed"
+    cat "gcc/limitx.h" "gcc/glimits.h" "gcc/limity.h" \
+        >"%{install-root}/$target_libgcc_dir/include-fixed/limits.h"