ci: add Linux aarch64 libretro build

.gitlab-ci.yml

@@ -27,6 +27,10 @@ include:
   - project: 'libretro-infrastructure/ci-templates'
     file: '/linux-x64.yml'
     
+  # Linux ARM 64-bit
+  - project: 'libretro-infrastructure/ci-templates'
+    file: '/linux-aarch64.yml'
+    
   # Linux 32-bit
   - project: 'libretro-infrastructure/ci-templates'
     file: '/linux-i686.yml'
@@ -135,6 +139,12 @@ libretro-build-linux-x64:
     - .libretro-linux-x64-make-default
     - .core-defs
 
+# Linux ARM 64-bit
+libretro-build-linux-aarch64:
+  extends:
+    - .libretro-linux-aarch64-make-default
+    - .core-defs
+
 # Linux 32-bit
 libretro-build-linux-i686:
   extends: