GHA: Add GCC 16 to CI

.github/workflows/unit-tests.yml

@@ -108,6 +108,7 @@ jobs:
           #   Use (compiler) default C++ 17 standard
           #   Use default cmake
           - { compiler: gcc-14,   os: ubuntu-24.04, type: Debug }
+          - { compiler: gcc-16,   os: ubuntu-24.04, type: Debug, "apt_key": "0x1E9377A2BA9EF27F", "apt_repo": "ppa:ubuntu-toolchain-r/test" }
           - { compiler: clang-18, os: ubuntu-24.04, type: Debug, externalSanitizer: true }
           - { compiler: clang-21, os: ubuntu-latest, type: Debug, init_llvm: true}
 
@@ -179,6 +180,12 @@ jobs:
               clang_version=${compiler#clang-*}
               wget -qO- "https://apt.llvm.org/llvm.sh" | sudo bash -s -- "${clang_version}"
             fi
+            if [[ -n "${{matrix.apt_key}}" ]]; then
+              tools/ci/add-apt-keys.sh "${{matrix.apt_key}}"
+            fi
+            if [[ -n "${{matrix.apt_repo}}" ]]; then
+              tools/ci/add-apt-repositories.sh "${{matrix.apt_repo}}"
+            fi
             sudo apt-get -o Acquire::Retries=5 update
             sudo apt-get -o Acquire::Retries=5 -y -q --no-install-suggests --no-install-recommends install gettext libsdl2-dev libsdl2-mixer-dev libcurl4-openssl-dev libbz2-dev libminiupnpc-dev liblua5.2-dev $compiler
           fi

tools/ci/add-apt-keys.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+#
+# Copyright 2023-2024 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+#      http://www.boost.org/LICENSE_1_0.txt)
+#
+# Add APT keys
+# - Each argument should be a key URL or a key ID (0x...)
+# - $NET_RETRY_COUNT is the amount of retries attempted
+
+set -eu
+
+if curl --retry-all-errors 2>&1 | grep -iq unknown; then
+    # --retry-all-errors not available
+    curl_extra_options=""
+else
+    curl_extra_options="--retry-all-errors"
+fi
+
+function do_add_key
+{
+    key_url=$1
+    # If a keyserver URL (e.g. http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x1E9377A2BA9EF27F)
+    # use the hash as the filename,
+    # if it is an ID, e.g. 0x1E9377A2BA9EF27F, use it as the filename, and http://keyserver.ubuntu.com/pks/lookup as the URL
+    # else assume the URL contains a filename, e.g. https://apt.llvm.org/llvm-snapshot.gpg.key
+    if [[ "$key_url" =~ .*keyserver.*search=0x([A-F0-9]+) ]]; then
+        keyfilename="${BASH_REMATCH[1]}.key"
+    elif [[ $key_url =~ ^0x[A-F0-9]+$ ]]; then
+        keyfilename=${key_url#0x}.key
+        key_server="keyserver.boost.org"
+        key_url="https://$key_server/pks/lookup?op=get&search=$key_url"
+    else
+        keyfilename=$(basename -s .key "$key_url")
+    fi
+    echo -e "\tDownloading APT key from '$key_url' to '$keyfilename'"
+    if ! curl ${curl_extra_options} --connect-timeout 15 -sSL --retry "${NET_RETRY_COUNT:-5}" "$key_url" | sudo gpg --dearmor -o "/etc/apt/trusted.gpg.d/${keyfilename}"; then
+        echo "Failed downloading $keyfilename"
+        return 1
+    fi
+}
+
+for key_url in "$@"; do
+    [[ -n $key_url ]] || continue
+    do_add_key "$key_url"
+done

tools/ci/add-apt-repositories.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# Copyright 2023 Sam Darwin
+# Copyright 2023-2024 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+#      http://www.boost.org/LICENSE_1_0.txt)
+#
+# Add APT keys, i.e. wrapper around add-apt-repository
+# - Each argument should be a repository name
+# - $NET_RETRY_COUNT is the amount of retries attempted
+
+set -eu
+
+function do_add_repository {
+    name=$1
+    echo -e "\tAdding repository $name"
+    for i in $(seq "${NET_RETRY_COUNT:-3}"); do
+        if [[ $i -ne 1 ]]; then
+            sleep 10
+            echo -e "\tRetrying"
+        fi
+        if sudo -E apt-add-repository -y "$name"; then
+            return 0
+        fi
+    done
+    echo "Failed adding $name"
+    return 1 # Failed
+}
+
+for repo_name in "$@"; do
+    [[ -n $repo_name ]] || continue
+    do_add_repository "$repo_name"
+done