Use env var for appimagetool

.github/workflows/build_linux.yml

@@ -42,7 +42,7 @@ jobs:
         run: |
           wget https://github.com/AppImage/appimagetool/releases/download/continuous/appimagetool-$LINUX_ARCH.AppImage
           chmod +x appimagetool-$LINUX_ARCH.AppImage
-          ln -sfv appimagetool-$LINUX_ARCH.AppImage ~/.local/bin/appimagetool
+          export APPIMAGE_TOOL_EXEC="$(pwd)/appimagetool-$LINUX_ARCH.AppImage"
           echo "BUILD_VERSION=$(python pkgutils.py version)" >> $GITHUB_OUTPUT
           python pkgutils.py build-appimage $LINUX_TAG $LINUX_ARCH $PYTHON_VERSION
 

utils/build_appimage.py

@@ -114,10 +114,11 @@ def appImage(args: argparse.Namespace) -> None:
     shutil.copyfile(libPath / "libxcb-cursor.so.0", appLibs / "libxcb-cursor.so.0")
 
     # Build Image
+    appToolExec = os.environ.get("APPIMAGE_TOOL_EXEC", "appimagetool")
     env = os.environ.copy()
     env["ARCH"] = mArch
     systemCall([
-        "appimagetool", "--no-appstream", "--updateinformation",
+        appToolExec, "--no-appstream", "--updateinformation",
         f"gh-releases-zsync|vkbo|novelwriter|latest|novelwriter-*-{mArch}.AppImage.zsync",
         str(appDir), bldImg
     ], cwd=bldDir, env=env)