osx does not find the default config file

[Antoine Martin]

This means that OSX gets its defaults from the default config object, which may have different values.

This leads to discrepancies (like the lack of compressors or packet-encoders which was worked around in r7090).

[Antoine Martin]

Refactored the code to make it cleaner / clearer in r7095.

We now have 2 config locations exposed via the xpra.platform.path module: the system default (get_global_conf_dir) and the user config (get_default_conf_dir).

The system default config directory can be overriden using the environment variable XPRA_SYSCONF_DIR, otherwise it is set to:

• C:\Program Files\Xpra\ (or whatever the application's installation directory is) on win32
• /Volumes/Xpra/Xpra.app/Contents/Resources/ (or whatever the path to the resources directory is) on osx
• /etc/xpra or /usr/local/etc on posix

The user's configuration directory can be overriden using the environment variable XPRA_CONF_DIR, otherwise it is set to:

• ~/.xpra on posix and osx
• %APPDATA%\Xpra on win32 (ie: C:\Documents and Settings\Username\Application Data\Xpra)

[migration script]

this ticket has been moved to: ​https://github.com/Xpra-org/xpra/issues/624