Add constructor to set up heap before libc

The dynamic heap used by rumprun apps needs to be configured before libc
is initialised. The dynamic heap also depends on malloc, so it needs to
run after the vsyscall function has been configured.

Signed-off-by: Curtis Millar <curtis.millar@data61.csiro.au>

rumprun: include configs

since global autoconf is removed, we need to manually add
back the kernel config and rumprun_Config

trivial: name threads + minor style fixes

seL4: run astyle over project

seL4: Add CAmkES support