build tools: add make_vendor_tarball script

build_tools/make_vendor_tarball.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+# Script to generate a tarball of vendored (downloaded) Rust dependencies
+# and the cargo configuration to ensure they are used
+# This tarball should be unpacked into a fish source directory
+# Outputs to $FISH_ARTEFACT_PATH or ~/fish_built by default
+
+# Exit on error
+set -e
+
+# We need GNU tar as that supports the --mtime and --transform options
+TAR=notfound
+for try in tar gtar gnutar; do
+  if $try -Pcf /dev/null --mtime now /dev/null >/dev/null 2>&1; then
+    TAR=$try
+    break
+  fi
+done
+
+if [ "$TAR" = "notfound" ]; then
+  echo 'No suitable tar (supporting --mtime) found as tar/gtar/gnutar in PATH'
+  exit 1
+fi
+
+# Get the current directory, which we'll use for telling Cargo where to find the sources
+wd="$PWD"
+
+# Get the version from git-describe
+VERSION=$(git describe --dirty 2>/dev/null)
+
+# The name of the prefix, which is the directory that you get when you untar
+prefix="fish-$VERSION"
+
+# The path where we will output the tar file
+# Defaults to ~/fish_built
+path=${FISH_ARTEFACT_PATH:-~/fish_built}/$prefix-vendor.tar
+
+# Clean up stuff we've written before
+rm -f "$path" "$path".xz
+
+# Work in a temporary directory to avoid clobbering the source directory
+PREFIX_TMPDIR=$(mktemp -d)
+cd "$PREFIX_TMPDIR"
+
+mkdir .cargo
+cargo vendor --manifest-path "$wd/Cargo.toml" > .cargo/config
+
+# vendoring drags in a lot of Windows dependencies, which makes the resulting tarball enormous
+# cargo can't be told only to support a particular platform
+# see https://github.com/rust-lang/cargo/issues/7058
+# workaround below from https://github.com/rust-lang/cargo/issues/7058#issuecomment-751856262
+rm -r vendor/winapi*/lib/*.a
+
+tar cfvJ $path.xz vendor .cargo
+
+cd -
+rm -r "$PREFIX_TMPDIR"
+
+# Output what we did, and the sha256 hash
+echo "Tarball written to $path".xz
+openssl dgst -sha256 "$path".xz