Bug 1688039 - Build grcov with Clang. r=calixte DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D102723

taskcluster/ci/toolchain/grcov.yml

@@ -20,6 +20,8 @@ linux64-grcov:
     fetches:
         toolchain:
             - linux64-rust-1.47
+            - linux64-clang
+            - linux64-binutils
 
 macosx64-grcov:
     treeherder:

taskcluster/scripts/misc/build-grcov.sh

@@ -8,6 +8,12 @@ PROJECT=grcov
 case "$(uname -s)" in
 Linux)
     COMPRESS_EXT=xz
+
+    export CC=clang
+    export CXX=clang++
+    export RUSTFLAGS=-Clinker=clang++
+
+    export PATH="$MOZ_FETCHES_DIR/clang/bin:$MOZ_FETCHES_DIR/binutils/bin:$PATH"
     ;;
 MINGW*)
     UPLOAD_DIR=$PWD/public/build