Bug 1654882 - Add a makecab toolchain. r=froydnj

This adds a makecab toolchain for Linux. It's not hooked anywhere
because bug 1654994 will also move the use of makecab to upload-symbols
tasks, so hooking the toolchain up with builds would be a waste of
time.

Differential Revision: https://phabricator.services.mozilla.com/D84789

taskcluster/ci/fetch/toolchains.yml

@@ -492,3 +492,10 @@ sonatype-nexus:
         artifact-name: sonatype-nexus.tar.zst
         strip-components: 1
         add-prefix: sonatype-nexus/
+
+makecab:
+    description: makecab source code
+    fetch:
+        type: git
+        repo: https://github.com/luser/rust-makecab/
+        revision: d2bc6797648b7a834782714a55d339d2fd4e58c8

taskcluster/ci/toolchain/misc.yml

@@ -305,3 +305,16 @@ win64-winchecksec:
         toolchain:
             - linux64-clang-win-cross
             - linux64-liblowercase
+
+linux64-makecab:
+    description: "makecab toolchain build"
+    treeherder:
+        symbol: TL(cab)
+    run:
+        script: build-makecab.sh
+        toolchain-artifact: public/build/makecab.tar.zst
+    fetches:
+        fetch:
+            - makecab
+        toolchain:
+            - linux64-rust-1.41

taskcluster/scripts/misc/build-makecab.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+set -x -e -v
+
+export PATH="$MOZ_FETCHES_DIR/rustc/bin:$PATH"
+
+cd $MOZ_FETCHES_DIR/rust-makecab
+
+cargo build --verbose --release
+
+mkdir makecab
+cp target/release/makecab makecab/
+tar -c makecab | $GECKO_PATH/taskcluster/scripts/misc/zstdpy > makecab.tar.zst
+mkdir -p $UPLOAD_DIR
+cp makecab.tar.zst $UPLOAD_DIR