linux/appimage: update libXft from 2.3.8 to 2.3.9

An up to date version of libXft is still needed because Ubuntu 22.04
still has 2.3.4, which can cause the app not to launch if an emoji font
is installed on the host.

appimage/AppImageBuilder.yml

@@ -10,9 +10,10 @@ script:
   - cd "$BUILD_DIR"
 
   # Build a recent version of libXft first. This fixes an issue where the app won't start with libXft 2.3.3 if an emoji font is installed on the system.
-  - curl -L https://xorg.freedesktop.org/releases/individual/lib/libXft-2.3.8.tar.xz -o libXft.tar.xz
+  - curl -fL https://xorg.freedesktop.org/releases/individual/lib/libXft-2.3.9.tar.xz -o libXft.tar.xz
+  - sha256sum libXft.tar.xz
   - tar xvf libXft.tar.xz
-  - cd libXft-2.3.8
+  - cd libXft-*
   - ./configure --prefix="$TARGET_APPDIR/usr" --disable-static
   - make -j$(nproc)
   - make install-strip