[PATCH 00 of 11] RFC: hvmloader SeaBIOS integration

[Ian Campbell <ian.campbell@citrix.com>]

The following patchset is a WIP/RFC/vagueidea enabling the build of
two versions of hvmloader, the first using ROMBIOS and the second
using SeaBIOS.

This is achieved by compiling hvmloader.c multiple times which
required a certain amount of disentanglement and reworking to avoid
the need to compile other files more than once. The bulk of the series
consists of that work.

It's not clear to me that this is preferable to building a single
hvmloader which can pollinate a VM with either BIOS.

The final patch, which actually adds the SeaBIOS support, includes a
slew of ugly #ifdef'ery. Since it is not clear at the moment which of
this functionality is not needed with SeaBIOS and which is simply not
ready/working/tested yet I didn't put a great deal of effort into
refactoring that aspect.

It's a great shame that the choice of hvmloader binary was exposed to
users through the config file format. We'll have to cross that bridge
later I guess...