util/xmlconfig: Add a non-XML format for driconf options on Android
final commit explains it:
util/xmlconfig: Use a non-xml-string encoding of driver options for Android.
On Android, we don't have user-defined drircs to parse, or even the
Mesa-defined drirc. We don't need the option descriptions, or the ranges
for values, either. Just "this driver has an option of this name and type
and this default value" so that the rest of Mesa internals can interact
with driconf options like normal. Nothing outside of mesa on android uses
the entrypoints to get the XML.
AOSP really doesn't want to carry around a 150k XML parsing library for an
actually unused feature.
We can drop that dependency by making a trivial string encoding (so we can
reuse the rest of the Mesa plumbing) that we parse directly to values at
screen init time.
It's got a unit test to sanity check it, but I haven't tested an actual Android driver build. Yet.