Add cross build/testing for ARM.

Author: Rot127

.github/workflows/CrossBuilds.yml

@@ -80,6 +80,17 @@ jobs:
               packages: 'gcc-powerpc64-linux-gnu g++-powerpc64-linux-gnu binutils-powerpc64-linux-gnu libc6-dev-ppc64-cross qemu-user-static',
               cross_file: 'cross_configs/linux_ppc64_ubuntu24.cmake',
             }
+          - {
+              name: 'QEMU Linux ARM',
+              os: ubuntu-24.04,
+              arch: x64,
+              build-system: 'cmake',
+              diet-build: 'OFF',
+              build_type: 'Debug',
+              diet_build: false,
+              packages: 'gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf binutils-arm-linux-gnueabihf libc6-dev-armhf-cross qemu-user-static',
+              cross_file: 'cross_configs/linux_arm_ubuntu24.cmake',
+            }
           - {
               name: '[BUILD ONLY] Windows i686 mingw',
               os: ubuntu-24.04,

cross_configs/linux_arm_ubuntu24.cmake

@@ -0,0 +1,17 @@
+# This example file is for builds on Ubunutu 24.04.
+# sudo apt install gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf binutils-arm-linux-gnueabihf libc6-dev-armhf-cross qemu-user-static
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR arm)
+
+set(CMAKE_C_COMPILER   arm-linux-gnueabihf-gcc)
+set(CMAKE_ASM_COMPILER arm-linux-gnueabihf-gcc)
+set(CMAKE_CROSS_COMPILING 1)
+
+set(CMAKE_SYSROOT /usr/arm-linux-gnueabihf)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+
+set(CMAKE_CROSSCOMPILING_EMULATOR qemu-arm-static;-L;${CMAKE_SYSROOT})
+