Merge tag '12.0-beta1' into jgrpp-beta

# Conflicts:
#	CMakeLists.txt
#	bin/ai/CMakeLists.txt
#	bin/game/CMakeLists.txt
#	src/build_vehicle_gui.cpp
#	src/console_cmds.cpp
#	src/core/overflowsafe_type.hpp
#	src/fios.cpp
#	src/lang/english.txt
#	src/lang/german.txt
#	src/lang/korean.txt
#	src/lang/polish.txt
#	src/network/core/game_info.cpp
#	src/network/core/game_info.h
#	src/network/core/tcp_game.cpp
#	src/network/core/tcp_game.h
#	src/network/network.cpp
#	src/network/network_client.cpp
#	src/network/network_client.h
#	src/network/network_coordinator.cpp
#	src/network/network_gui.cpp
#	src/network/network_server.cpp
#	src/network/network_server.h
#	src/newgrf_engine.cpp
#	src/openttd.cpp
#	src/rev.cpp.in
#	src/settings_type.h
#	src/train.h
#	src/train_cmd.cpp

.github/workflows/release.yml

@@ -374,14 +374,19 @@ jobs:
         include:
         - container_image: "ubuntu:18.04"
           bundle_name: "bionic"
+          compiler: "g++-8"
         - container_image: "ubuntu:20.04"
           bundle_name: "focal"
+          compiler: "g++"
         - container_image: "ubuntu:20.10"
           bundle_name: "groovy"
+          compiler: "g++"
         - container_image: "debian:buster"
           bundle_name: "buster"
+          compiler: "g++"
         - container_image: "debian:bullseye"
           bundle_name: "bullseye"
+          compiler: "g++"
 
     runs-on: ubuntu-20.04
     container:
@@ -407,7 +412,7 @@ jobs:
         apt-get install -y --no-install-recommends \
           cmake \
           debhelper \
-          g++ \
+          ${{ matrix.compiler }} \
           git \
           make \
           openssl \
@@ -434,7 +439,7 @@ jobs:
         cd build
 
         echo "::group::CMake"
-        cmake ${GITHUB_WORKSPACE} \
+        CXX=${{ matrix.compiler }} cmake ${GITHUB_WORKSPACE} \
           -DCMAKE_BUILD_TYPE=RelWithDebInfo \
           -DCMAKE_INSTALL_PREFIX=/usr \
           # EOF