Autobuild: Add Linux .deb aarch64 (Raspberry) 64bit builds

.github/autobuild/README.md

@@ -4,4 +4,7 @@ The scripts in this folder are used by the Github autobuild actions in .github/w
 They are responsible for setting up the Github environment, building the binaries and passing the resulting artifacts back to the workflow.
 
 The scripts may work outside of Github, but haven't been designed or tested for that use case.
+Some of the scripts modify global system settings, install software or create files in directories which are usually managed by package managers.
+In short: They should probably only used in throw-away environments.
+
 See the various platform-specific build scripts in their own folders for standalone builds (e.g. windows/deploy_windows.ps1).

.github/autobuild/linux_deb.sh

@@ -14,6 +14,9 @@ case "${TARGET_ARCH}" in
     armhf)
         ABI_NAME="arm-linux-gnueabihf"
         ;;
+    arm64)
+        ABI_NAME="aarch64-linux-gnu"
+        ;;
     *)
         echo "Unsupported TARGET_ARCH ${TARGET_ARCH}"
         exit 1
@@ -37,7 +40,9 @@ setup_cross_compilation_apt_sources() {
         return
     fi
     sudo dpkg --add-architecture "${TARGET_ARCH}"
+    # Duplicate the original Ubuntu sources and modify them to refer to the TARGET_ARCH:
     sed -rne "s|^deb.*/ ([^ -]+(-updates)?) main.*|deb [arch=${TARGET_ARCH}] http://ports.ubuntu.com/ubuntu-ports \1 main universe multiverse restricted|p" /etc/apt/sources.list | sudo dd of=/etc/apt/sources.list.d/"${TARGET_ARCH}".list
+    # Now take the original Ubuntu sources and limit those to the build host (i.e. non-TARGET_ARCH) architectures:
     sudo sed -re 's/^deb /deb [arch=amd64,i386] /' -i /etc/apt/sources.list
 }
 
@@ -50,10 +55,10 @@ setup_cross_compiler() {
     sudo update-alternatives --install "/usr/bin/${ABI_NAME}-g++" g++ "/usr/bin/${ABI_NAME}-g++-${GCC_VERSION}" 10
     sudo update-alternatives --install "/usr/bin/${ABI_NAME}-gcc" gcc "/usr/bin/${ABI_NAME}-gcc-${GCC_VERSION}" 10
 
-    if [[ "${TARGET_ARCH}" == armhf ]]; then
-        # Ubuntu's Qt version only ships a profile for gnueabi, but not for gnueabihf. Therefore, build a custom one:
+    # Ubuntu's Qt version only ships a profile for gnueabi, but not for gnueabihf or aarch64. Therefore, build a custom one:
+    if [[ $ABI_NAME ]]; then
         sudo cp -R "/usr/lib/${ABI_NAME}/qt5/mkspecs/linux-arm-gnueabi-g++/" "/usr/lib/${ABI_NAME}/qt5/mkspecs/${ABI_NAME}-g++/"
-        sudo sed -re 's/-gnueabi/-gnueabihf/' -i "/usr/lib/${ABI_NAME}/qt5/mkspecs/${ABI_NAME}-g++/qmake.conf"
+        sudo sed -re "s/arm-linux-gnueabi/${ABI_NAME}/" -i "/usr/lib/${ABI_NAME}/qt5/mkspecs/${ABI_NAME}-g++/qmake.conf"
     fi
 }
 

.github/workflows/autobuild.yml

@@ -209,6 +209,13 @@ jobs:
             base_command:           TARGET_ARCH=armhf ./.github/autobuild/linux_deb.sh
             run_codeql:             false
 
+          - config_name:            Linux .deb arm64 (artifacts)
+            target_os:              linux
+            building_on_os:         ubuntu-22.04
+            building_container:     ubuntu:18.04
+            base_command:           TARGET_ARCH=arm64 ./.github/autobuild/linux_deb.sh
+            run_codeql:             false
+
           - config_name:            MacOS (artifacts)
             target_os:              macos
             building_on_os:         macos-12