docs: describe the QEMU build system structure / design

Developers who are new to QEMU, or have a background familiarity
with GNU autotools, can have trouble getting their head around the
home-grown QEMU build system. This document attempts to explain
the structure / design of the configure script and the various
Makefile pieces that live across the source tree.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1443102098-13642-1-git-send-email-berrange@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MAINTAINERS

@@ -1408,3 +1408,11 @@ M: Stefan Hajnoczi <stefanha@redhat.com>
 L: qemu-block@nongnu.org
 S: Supported
 F: tests/image-fuzzer/
+
+
+Documentation
+-------------
+Build system architecture
+M: Daniel P. Berrange <berrange@redhat.com>
+S: Odd Fixes
+F: docs/build-system.txt