On non-Windows, the icons are installed on the system's icon directory,
so installing our index.theme might override the system's one. Since
it's highly unlikely the theme index is missing on non-Windows, just
don't install it.
Install all icons on Windows, as well as a theme index because the
system doesn't have one and one is required.
Also install the theme index on non-Windows, although it shouldn't
be necessary because the system is likely to provide one.
an arglist have the 'function/method' icon, all others have the
'variable' icon.
Note: XPMs were created from the PNGs with the ImageMagick 'convert'
program.
git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@3930 ea778897-0a13-0410-b9d1-a72fbfd435f5
