Try out building as nobody

.drone.yml

@@ -7,7 +7,13 @@ steps:
         commands:
             - find usr/local/bin -type f -exec echo Testing {} \; -exec shellcheck {} \;
     -   name: build arch package
-        image: archlinux/archlinux
+        image: archlinux/archlinux:base-devel
         commands:
-            - cd _pkg
-            - makepkg -cs
+            - pacman -Syu
+            - mkdir /home/build
+            - cp -r /drone/src /home/build
+            - chgrp nobody /home/build
+            - chmod g+ws /home/build
+            - setfacl -m u::rwx,g::rwx /home/build
+            - setfacl -d --set u::rwx,g::rwx,o::- /home/build
+            - sudo -u nobody cd _pkg makepkg -cs