osdep.h has a few things which are really compiler specific;
move them to compiler.h, and include compiler.h from osdep.h.
Backports commit 4912086865083a008f4fb73173fd0ddf2206c4d9 from qemu
Including qemu-common.h from other header files is generally a bad
idea, because it means it's very easy to end up with a circular
dependency. For instance, if we wanted to include memory.h from
qom/cpu.h we'd end up with this loop:
memory.h -> qemu-common.h -> cpu.h -> cpu-qom.h -> qom/cpu.h -> memory.h
Remove the include from memory.h. This requires us to fix up a few
other files which were inadvertently getting declarations indirectly
through memory.h.
The biggest change is splitting the fprintf_function typedef out
into its own header so other headers can get at it without having
to include qemu-common.h.
Backports commit fba0a593b2809ecdda68650952cf3d3332ac1990 from qemu
