Split clock code into common and arch specific code

Move console code outside into arch-generic folder

Add ARM support to seL4 Rumprun platform layer

Add fixes to support gcc-6

Better separate bottom and toplevel rumprun builds

The platform builds has two steps, build and then install. The way the
original rules are set up require this to be done in separate make
invocations. Splitting the platform builds up into different top level
and bottom level stages means that we need to have top level and bottom
level build and install stages also.

Remove seL4 stage directory hard coded paths

These are now passed in from Kbuild as environment variables

seL4: Remove dead variable

This was never used (even when it was initially added)

seL4: Mark ${MAINOBJ} target as .PHONY

This file target depends on libraries passed in as MAINOBJ_LD_FLAGS
which means we don't track its dependencies properly.

seL4: Move platformlibs dependency to correct rule

platformlibs builds libraries that ${MAINOBJ} links against but not
${INTERMEDIATE_BASEFILE}

seL4: Redefine CRT and FINOBJFILES

This is in order to reduce the chance of name collisions with non seL4
related definitions

seL4: Touch up echo build messages

seL4: Add more finegrained make rules

This is to make it possible to have better fine grained control of what
targets are built to get better incremental compilation and parallel
performance

sel4: Remove PHONY archdir make rule

This wasn't being tracked as a dependency properly.

Add librumpsel4_stdio rump kernel module

Provides stdio support through shared memory circular buffers and seL4
notification objects

Add build support for arbitrary source locations

seL4: Add CAmkES support

seL4: Change to use simple implementation

seL4: Fix typo in Makefile variable name

seL4: Use correct CRT and FIN OBJ files

Now that the linker scripts have been fixed up, we can use correct files
without getting linker errors.

seL4: Create rumprunlibs.mk

This file contains needed rump kernel and rumprun build and environment
parameters for including into other makefiles

seL4: Try and simplify linker scripts

Because seL4 isn't a bare metal platform we can use more of the default
linker script.

seL4: Add x86_64 support to rumprun

seL4: Add seL4 as a target rumprun platform