Add protobuf compiler dependency

.github/workflows/libclient-build.yaml

@@ -171,7 +171,7 @@ jobs:
         env:
           LINKER: ${{ matrix.build-env.linker }}
         run: |
-          cat >> ~/.cargo/config <<EOF
+          cat >> $CARGO_HOME/config.toml <<EOF
           [target.$TARGET]
           linker = "$LINKER"
           EOF

generate_matrix.py

@@ -31,19 +31,28 @@
                 "lib-suffix": ".so",
                 "triple": "x86_64-unknown-linux-gnu",
                 "install-cmd": "sudo apt-get update && sudo apt-get install",
+                "req-pkg": "protobuf-compiler"
+                } | {
+                ### Rust container on Debian 10
+                ### (libc: Deb-10's v2.28 vs Ubuntu-20.04 v2.31)
+                "container": "rust:buster",
+                "install-cmd": "bash ./util.sh add_deb_repos && apt-get update && apt-get install -y",
+                "req-pkg": "python3 clang libclang-dev cmake make gh protobuf-compiler/buster-backports",
                 },
         "macos": {
                 "runner": "macos-latest",
                 "lib-prefix": "lib",
                 "lib-suffix": ".dylib",
                 "triple": "x86_64-apple-darwin",
+                "install-cmd": "brew install",
+                "req-pkg": "protobuf",
             },
         "windows": {
                 "runner": "windows-latest",
                 "lib-suffix": ".dll",
                 "triple": "x86_64-pc-windows",
                 "install-cmd": "choco install",
-                "req-pkg": "nasm",  # for boringssl
+                "req-pkg": "nasm protoc",  # nasm: for boringssl
                 "rust-flags": "-C target-feature=+crt-static",
                     # Static linking to remove MSVC dependendency. See:
                     # zkgroup/ffi/node/Makefile
@@ -57,7 +66,10 @@ def cross_template(arch, subarch="", env="gnu", vendor="unknown", sys_os="linux"
     cross_dict = {
             "target": f"{arch}{subarch}-{vendor}-{sys_os}-{env}",
             "req-pkg": " ".join((
-                f"{compiler}-{arch}-{sys_os}-{env}" for compiler in compilers.values()
+                host_dict["req-pkg"],
+                " ".join((
+                    f"{compiler}-{arch}-{sys_os}-{env}" for compiler in compilers.values()
+                    )),
                 )),
             "linker": f"{arch}-{sys_os}-{env}-{compilers['C']}",
             "build-env-vars": " ".join((
@@ -69,12 +81,7 @@ def cross_template(arch, subarch="", env="gnu", vendor="unknown", sys_os="linux"
     return host_dict | cross_dict
 
 build_envs = [
-        hosts["linux"] | {
-            ### Rust container on Debian 10
-            "container": "rust:buster",
-            "install-cmd": "bash ./util.sh add_gh_ppa && apt-get update && apt-get install -y",
-            "req-pkg": "python3 clang libclang-dev cmake make gh",
-            },
+        hosts["linux"],
         hosts["macos"],
         hosts["windows"],
         ### Cross-compiling ###

util.sh

@@ -128,12 +128,17 @@ gradle_deps_vers () {
 		done
 }
 
-add_gh_ppa() {
+add_deb_repos() {
+	# Installing GitHub CLI `gh` on Debian container
 	# From https://github.com/cli/cli/blob/trunk/docs/install_linux.md, sans `sudo` (for docker)
 	type -p curl >/dev/null || apt install curl -y
 	curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg \
 	&& chmod go+r /usr/share/keyrings/githubcli-archive-keyring.gpg \
 	&& echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | tee /etc/apt/sources.list.d/github-cli.list > /dev/null
+
+	# For installing newer protobuf-compiler than available on Debian 10 (buster)
+	# Need protoc>v3.12.0, or get "protoc failed: Unknown flag: --experimental_allow_proto3_optional"
+	echo "deb http://deb.debian.org/debian buster-backports main" > /etc/apt/sources.list.d/buster-backports.list
 }
 
 "$@"