Merge branch 'baserock/samthursfield/build-essential-2-rebase'

Baserock no longer requires a staging filler to build. Instead, the
tools of the host system are used to bootstrap a compiler which then
builds the rest of the system in a staging chroot, as was previously
done with the staging filler.

There are likely to be errors if you do try to build with a staging
filler, because it will interfere with the build-essential bootstrap
process.

Versions of Morph before the following commit can no longer build
Baserock systems:

    commit 13cded5a796889c748e60ffa17fc92bad592bf39
    Merge: 8046bf0 4b5f45f
    Author: Sam Thursfield <sam.thursfield@codethink.co.uk>
    Date:   Fri Mar 15 11:05:07 2013 +0000

        Merge branch 'samthursfield/arch'

        Reviewed-By: concensus

18 files changed, 640 insertions, 77 deletions

diff --git a/base-system-armv7-highbank.morph b/base-system-armv7-highbank.morph
index 22005cb..193ae6e 100644
--- a/base-system-armv7-highbank.morph
+++ b/base-system-armv7-highbank.morph
@@ -9,22 +9,22 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-armv7-highbank",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/base-system-armv7-versatile.morph b/base-system-armv7-versatile.morph
index 04db502..259c3a1 100644
--- a/base-system-armv7-versatile.morph
+++ b/base-system-armv7-versatile.morph
@@ -9,22 +9,22 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-armv7-versatile",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/base-system-x86_32-generic.morph b/base-system-x86_32-generic.morph
index 2e29dbe..dd687d0 100644
--- a/base-system-x86_32-generic.morph
+++ b/base-system-x86_32-generic.morph
@@ -9,22 +9,22 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-x86_32-generic",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/base-system-x86_64-generic.morph b/base-system-x86_64-generic.morph
index 4ae4e71..6340a43 100644
--- a/base-system-x86_64-generic.morph
+++ b/base-system-x86_64-generic.morph
@@ -9,22 +9,22 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-x86_64-generic",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/bsp-armv7-highbank.morph b/bsp-armv7-highbank.morph
index 1a49c68..384189d 100644
--- a/bsp-armv7-highbank.morph
+++ b/bsp-armv7-highbank.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/bsp-armv7-versatile.morph b/bsp-armv7-versatile.morph
index 6f5e4a1..7c4e30d 100644
--- a/bsp-armv7-versatile.morph
+++ b/bsp-armv7-versatile.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/bsp-imx53.morph b/bsp-imx53.morph
index d8c668d..4c3aa38 100644
--- a/bsp-imx53.morph
+++ b/bsp-imx53.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/bsp-x86_32-generic.morph b/bsp-x86_32-generic.morph
index bd52755..02e68fd 100644
--- a/bsp-x86_32-generic.morph
+++ b/bsp-x86_32-generic.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/bsp-x86_64-generic.morph b/bsp-x86_64-generic.morph
index b984a13..4e6b15b 100644
--- a/bsp-x86_64-generic.morph
+++ b/bsp-x86_64-generic.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/build-essential.morph b/build-essential.morph
index 5a3fb2c..c8c9413 100644
--- a/build-essential.morph
+++ b/build-essential.morph
@@ -4,58 +4,318 @@
     "kind": "stratum",
     "chunks": [
         {
-            "name": "binutils",
+            "name": "stage1-binutils",
             "repo": "upstream:binutils-redhat",
-            "ref": "baserock/build-essential",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
             "build-depends": []
         },
         {
-            "name": "busybox",
-            "repo": "upstream:busybox",
-            "ref": "baserock/build-essential",
-            "build-depends": []
+            "name": "stage1-gcc",
+            "repo": "upstream:gcc-tarball",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils"
+            ]
         },
         {
-            "name": "eglibc",
+            "name": "stage2-linux-api-headers",
+            "repo": "upstream:linux",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc"
+            ]
+        },
+        {
+            "name": "stage2-eglibc",
             "repo": "upstream:eglibc2",
-            "ref": "baserock/2.15-build-essential",
-            "build-depends": []
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-linux-api-headers"
+            ]
         },
         {
-            "name": "fhs-dirs",
-            "repo": "baserock:baserock/fhs-dirs",
-            "ref": "master",
-            "build-depends": []
+            "name": "stage2-zlib",
+            "repo": "upstream:zlib",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc"
+            ]
         },
         {
-            "name": "gcc",
+            "name": "stage2-binutils",
+            "repo": "upstream:binutils-redhat",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc",
+                "stage2-zlib"
+            ]
+        },
+        {
+            "name": "stage2-gcc",
             "repo": "upstream:gcc-tarball",
-            "ref": "baserock/build-essential",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc",
+                "stage2-zlib"
+            ]
+        },
+        {
+            "name": "stage2-busybox",
+            "repo": "upstream:busybox",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc"
+            ]
+        },
+        {
+            "name": "stage2-fhs-dirs",
+            "repo": "baserock:baserock/fhs-dirs",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
             "build-depends": []
         },
         {
+            "name": "stage2-gawk",
+            "repo": "upstream:gawk",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc"
+            ]
+        },
+        {
+            "name": "stage2-make",
+            "repo": "upstream:make",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "bootstrap",
+            "prefix": "/tools",
+            "build-depends": [
+                "stage1-binutils",
+                "stage1-gcc",
+                "stage2-eglibc"
+            ]
+        },
+        {
+            "name": "fhs-dirs",
+            "repo": "baserock:baserock/fhs-dirs",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib"
+            ]
+        },
+        {
             "name": "linux-api-headers",
             "repo": "upstream:linux",
-            "ref": "baserock/build-essential",
-            "build-depends": []
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib"
+            ]
+        },
+        {
+            "name": "eglibc",
+            "repo": "upstream:eglibc2",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "linux-api-headers"
+            ]
+        },
+        {
+            "name": "zlib",
+            "repo": "upstream:zlib",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc"
+            ]
+        },
+        {
+            "name": "binutils",
+            "repo": "upstream:binutils-redhat",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc",
+                "zlib"
+            ]
+        },
+        {
+            "name": "busybox",
+            "repo": "upstream:busybox",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc"
+            ]
         },
         {
             "name": "gawk",
             "repo": "upstream:gawk",
-            "ref": "baserock/build-essential",
-            "build-depends": []
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc"
+            ]
+        },
+        {
+            "name": "gcc",
+            "repo": "upstream:gcc-tarball",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc",
+                "zlib"
+            ]
         },
         {
             "name": "make",
             "repo": "upstream:make",
-            "ref": "baserock/build-essential",
-            "build-depends": []
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc"
+            ]
         },
         {
             "name": "ccache",
             "repo": "upstream:ccache",
-            "ref": "baserock/build-essential",
-            "build-depends": []
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
+            "build-mode": "staging",
+            "prefix": "/usr",
+            "build-depends": [
+                "stage2-binutils",
+                "stage2-busybox",
+                "stage2-eglibc",
+                "stage2-fhs-dirs",
+                "stage2-gawk",
+                "stage2-gcc",
+                "stage2-linux-api-headers",
+                "stage2-make",
+                "stage2-zlib",
+                "eglibc",
+                "zlib"
+            ]
         }
     ]
 }
diff --git a/build-essential.morph.yaml b/build-essential.morph.yaml
new file mode 100644
index 0000000..79c6974
--- /dev/null
+++ b/build-essential.morph.yaml
@@ -0,0 +1,311 @@
+name: build-essential
+description: Toolchain stratum
+kind: stratum
+
+chunks:
+    # Stage 1: build a minimal cross compiler with the host's tools.
+    #
+    # Starting with a cross compiler ensures that (a) nothing from the host
+    # can leak into the build-essential artifacts, and (b) cross-compiling
+    # build-essential is fully tested and supported, since we always use the
+    # cross code paths.
+
+    - name: stage1-binutils
+      repo: upstream:binutils-redhat
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends: []
+
+    - name: stage1-gcc
+      repo: upstream:gcc-tarball
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+
+    # Stage 2: cross-build the whole of build-essential, using the host's tools
+    # but the cross-compiler toolchain.
+    #
+    # Stage 2 GCC outputs code for the same 'bootstrap' machine as stage 1 GCC,
+    # but because stage 2 GCC is also built to *run* on the bootstrap machine
+    # it can only execute inside the stage 3 chroot (due to being built against
+    # a libc with a non-standard prefix).
+
+    - name: stage2-linux-api-headers
+      repo: upstream:linux
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+
+    - name: stage2-eglibc
+      repo: upstream:eglibc2
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-linux-api-headers
+
+    - name: stage2-zlib
+      repo: upstream:zlib
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+
+    - name: stage2-binutils
+      repo: upstream:binutils-redhat
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+          - stage2-zlib
+
+    - name: stage2-gcc
+      repo: upstream:gcc-tarball
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+          - stage2-zlib
+
+    - name: stage2-busybox
+      repo: upstream:busybox
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+
+    - name: stage2-fhs-dirs
+      repo: baserock:baserock/fhs-dirs
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends: []
+
+    - name: stage2-gawk
+      repo: upstream:gawk
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+
+    - name: stage2-make
+      repo: upstream:make
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: bootstrap
+      prefix: /tools
+      build-depends:
+          - stage1-binutils
+          - stage1-gcc
+          - stage2-eglibc
+
+    # Stage 3: build the whole of build-essential again, this time using a
+    # staging area containing only the output of stage 2. The result of this
+    # build is fully reproducible.
+    #
+    # We do a switch-a-roo between stage 2 and 3: stages 2 chunks are all built
+    # to run on a host *-bootstrap-* while stage 3 chunks are built are native
+    # built for a *-baserock-* machine. This works, because the cross build was
+    # all for show (and cleanliness) and the binaries actually still run on the
+    # the host.
+    #
+    # After build-essential is built we do another trick: stage2-fhs-dirs
+    # symlinks /bin to /tools/bin and /lib to /tools/lib, while the stage 3
+    # chunks actually install things to those directories. FIXME: which breaks
+    # everything!!! This will have to change.
+    #
+
+    - name: fhs-dirs
+      repo: baserock:baserock/fhs-dirs
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+
+    - name: linux-api-headers
+      repo: upstream:linux
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+
+    - name: eglibc
+      repo: upstream:eglibc2
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - linux-api-headers
+
+    - name: zlib
+      repo: upstream:zlib
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+
+    - name: binutils
+      repo: upstream:binutils-redhat
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+          - zlib
+
+    - name: busybox
+      repo: upstream:busybox
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+
+    - name: gawk
+      repo: upstream:gawk
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+
+    - name: gcc
+      repo: upstream:gcc-tarball
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+          - zlib
+
+    - name: make
+      repo: upstream:make
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+
+    # Extras that need to be in build-essential but don't need bootstrapping.
+
+    - name: ccache
+      repo: upstream:ccache
+      ref: baserock/samthursfield/build-essential-2-rebase
+      build-mode: staging
+      prefix: /usr
+      build-depends:
+          - stage2-binutils
+          - stage2-busybox
+          - stage2-eglibc
+          - stage2-fhs-dirs
+          - stage2-gawk
+          - stage2-gcc
+          - stage2-linux-api-headers
+          - stage2-make
+          - stage2-zlib
+          - eglibc
+          - zlib
diff --git a/core.morph b/core.morph
index 56c046b..eb99e69 100644
--- a/core.morph
+++ b/core.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "build-essential"
         }
     ],
@@ -77,12 +77,6 @@
             ]
         },
         {
-            "name": "zlib",
-            "repo": "upstream:zlib",
-            "ref": "baserock/morph",
-            "build-depends": []
-        },
-        {
             "name": "autoconf",
             "repo": "upstream:autoconf",
             "ref": "baserock/build-essential",
@@ -139,8 +133,7 @@
             "ref": "baserock/morph-2.7",
             "build-depends": [
                 "openssl",
-                "readline",
-                "zlib"
+                "readline"
             ]
         },
         {
@@ -214,8 +207,7 @@
                 "error-perl-tarball",
                 "gettext",
                 "libexpat",
-                "openssl",
-                "zlib"
+                "openssl"
             ]
         },
         {
diff --git a/devel-system-armv7-highbank.morph b/devel-system-armv7-highbank.morph
index ab73541..17666c8 100644
--- a/devel-system-armv7-highbank.morph
+++ b/devel-system-armv7-highbank.morph
@@ -9,27 +9,27 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-armv7-highbank",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "tools",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/devel-system-armv7-versatile.morph b/devel-system-armv7-versatile.morph
index b10a52f..65f882e 100644
--- a/devel-system-armv7-versatile.morph
+++ b/devel-system-armv7-versatile.morph
@@ -9,27 +9,27 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-armv7-versatile",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "tools",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/devel-system-x86_32-generic.morph b/devel-system-x86_32-generic.morph
index c0f4b87..5ec40ec 100644
--- a/devel-system-x86_32-generic.morph
+++ b/devel-system-x86_32-generic.morph
@@ -9,27 +9,27 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-x86_32-generic",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "tools",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/devel-system-x86_64-generic.morph b/devel-system-x86_64-generic.morph
index 4872961..ae1db02 100644
--- a/devel-system-x86_64-generic.morph
+++ b/devel-system-x86_64-generic.morph
@@ -9,27 +9,27 @@
         {
             "morph": "build-essential",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "core",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "foundation",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "bsp-x86_64-generic",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         },
         {
             "morph": "tools",
             "repo": "baserock:baserock/morphs",
-            "ref": "master"
+            "ref": "baserock/samthursfield/build-essential-2-rebase"
         }
     ]
 }
diff --git a/foundation.morph b/foundation.morph
index 39e366d..da63c6a 100644
--- a/foundation.morph
+++ b/foundation.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "core"
         }
     ],
diff --git a/tools.morph b/tools.morph
index 7342cd2..7d95987 100644
--- a/tools.morph
+++ b/tools.morph
@@ -5,7 +5,7 @@
     "build-depends": [
         {
             "repo": "baserock:baserock/morphs",
-            "ref": "master",
+            "ref": "baserock/samthursfield/build-essential-2-rebase",
             "morph": "foundation"
         }
     ],