Bug 1691523 - Update Thunderbird toolchain builds to use a sysroot. r=justdave

Differential Revision: https://phabricator.services.mozilla.com/D104470

--HG--
extra : moz-landing-system : lando

taskcluster/ci/toolchain/libcxx.yml

@@ -16,6 +16,7 @@ linux64-clang-lib32cxx:
     worker-type: b-linux
     worker:
         max-run-time: 1800
+        docker-image: {in-tree: deb10-toolchain-build}
     run:
         using: comm-toolchain-script
         script: build-lib32cxx.sh
@@ -26,3 +27,4 @@ linux64-clang-lib32cxx:
         toolchain:
             - linux64-clang-11
             - linux64-gcc-7  # Use what linux64-clang uses
+            - linux64-toolchain-sysroot

taskcluster/ci/toolchain/libotr.yml

@@ -42,11 +42,12 @@ linux-aarch64-libotr:
     treeherder:
         symbol: TL(libotr-aarch64)
     worker:
-        docker-image: {in-tree: toolchain-arm64-build}
+        docker-image: {in-tree: deb10-toolchain-build}
     run:
         arguments: ['linux-aarch64']
     fetches:
         toolchain:
+            - linux64-aarch64-sysroot
             - linux64-clang-aarch64-cross
             - linux64-binutils
 

taskcluster/scripts/build-lib32cxx.sh

@@ -40,6 +40,7 @@ build() {
   local base_cmake_args="-G Ninja
     -DCMAKE_BUILD_TYPE=Release
     -DCMAKE_INSTALL_PREFIX=$PKGDIR/lib32-libc++
+    -DCMAKE_SYSROOT=$MOZ_FETCHES_DIR/sysroot
     -DLLVM_LIBDIR_SUFFIX=32
     -DLLVM_LINK_LLVM_DYLIB=ON
     -DLLVM_ENABLE_RTTI=ON