Fix up i386_sel4 arch after merge

make brace placement in public header typedef'd structs consistent

commit befa5866ee30d09c0c96e88af2eabff5911342ea performed this change
for struct definitions that did not also involve typedef, but omitted
the latter.

make brace placement in public header struct definitions consistent

placing the opening brace on the same line as the struct keyword/tag
is the style I prefer and seems to be the prevailing practice in more
recent additions.

these changes were generated by the command:

find include/ arch/*/bits -name '*.h' \
-exec sed -i '/^struct [^;{]*$/{N;s/\n/ /;}' {} +

and subsequently checked by hand to ensure that the regex did not pick
up any false positives.

Port muslc to seL4 build system and environment. Defines custom 'seL4' architectures for ARM and i386

make sys/procfs.h mostly work on most archs

these structures are purely for use by trace/debug tools and tools
working with core files. the definition of fpregset_t, which was
previously here, has been removed because it was wrong; fpregset_t
should be the type used in mcontext_t, not the type used in
ptrace/core stuff.

cleanup/debloat i386 user.h

preparing build system to handle ports - step 1