OSError: [Errno 18] Invalid cross-device link

[robertpro]

Hi, the configuration in my computer uses link to data files instead of partition (I feel comfortable with that),

But for Buildozer this is not working, when it tries to rename a file from /home/roberto/.buildozer/android/platform/android-sdk-linux to /media/datos/Documents/dev/tools/android/sdk, it just fails.

# ls -l /home/roberto/Downloads
lrwxrwxrwx. 1 roberto roberto 23 Aug  4  2017 /home/roberto/Downloads -> /media/datos/Downloads/

# grep path buildozer.spec 
android.ndk_path = /home/roberto/Documents/dev/tools/android/ndk
android.sdk_path = /home/roberto/Documents/dev/tools/android/sdk
android.ant_path = /home/roberto/Documents/dev/tools/android/ant

buildozer --verbose android debug
# Check configuration tokens
# Ensure build layout
# Check configuration tokens
# Read available permissions from api-versions.xml
# Preparing build
# Check requirements for android
# Run 'dpkg --version'
# Cwd None
/bin/sh: dpkg: command not found
# Search for Git (git)
#  -> found at /usr/bin/git
# Search for Cython (cython)
#  -> found at /media/datos/Documents/dev/tools/.virtualenvs/kivy/bin/cython
# Search for Java compiler (javac)
#  -> found at /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-5.b14.fc27.x86_64/bin/javac
# Search for Java keytool (keytool)
#  -> found at /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-5.b14.fc27.x86_64/jre/bin/keytool
# Install platform
# Run 'pip install -q  '
# Cwd None
# Android ANT is missing, downloading
# Downloading http://archive.apache.org/dist/ant/binaries/apache-ant-1.9.4-bin.tar.gz
# Run 'tar xzf apache-ant-1.9.4-bin.tar.gz'
# Cwd /home/roberto/.buildozer/android/platform
# Apache ANT installation done.
# Android SDK is missing, downloading
# Downloading http://dl.google.com/android/android-sdk_r21-linux.tgz
# Unpacking Android SDK
# Run 'tar xzf android-sdk_r21-linux.tgz'
# Cwd /home/roberto/.buildozer/android/platform
# Rename /home/roberto/.buildozer/android/platform/android-sdk-linux to /media/datos/Documents/dev/tools/android/sdk
Traceback (most recent call last):
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/bin/buildozer", line 11, in <module>
    sys.exit(main())
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/scripts/client.py", line 13, in main
    Buildozer().run_command(sys.argv[1:])
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/__init__.py", line 1058, in run_command
    self.target.run_commands(args)
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/target.py", line 92, in run_commands
    func(args)
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/target.py", line 102, in cmd_debug
    self.buildozer.prepare_for_build()
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/__init__.py", line 176, in prepare_for_build
    self.target.install_platform()
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/targets/android.py", line 468, in install_platform
    self._install_android_sdk()
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/targets/android.py", line 268, in _install_android_sdk
    cwd=self.buildozer.global_platform_dir)
  File "/media/datos/Documents/dev/tools/.virtualenvs/kivy/lib/python2.7/site-packages/buildozer/__init__.py", line 615, in file_rename
    rename(source, target)
OSError: [Errno 18] Invalid cross-device link

I will make a PR fixing this