fix(build): allow using --install and --offload simultaneously

Don't take the full (local) path of the package to install when using
--offload.

Fixes #194
Component: pkgctl build

src/lib/build/build.sh

@@ -200,7 +200,11 @@ pkgctl_build() {
 				;;
 			-I|--install)
 				(( $# <= 1 )) && die "missing argument for %s" "$1"
-				MAKECHROOT_OPTIONS+=("-I" "$(realpath "$2")")
+				if (( OFFLOAD )); then
+					MAKECHROOT_OPTIONS+=("-I" "$2")
+				else
+					MAKECHROOT_OPTIONS+=("-I" "$(realpath "$2")")
+				fi
 				warning 'installing packages into the chroot may break reproducible builds, use with caution!'
 				shift 2
 				;;