riscv: Add FENCE.I instruction in ELF loading code

Writes to executable memory may not become visible to execution until
after FENCE.I instruction. This prevents programs loaded by this
function crashing due to invalid program instructions.

Trivial: Style fix

make the style checker happy

seL4_libs: remove autoconf.h from seL4_libs

this commit removes autoconf.h generation from each lib and
append '#include <<lib_name>/gen_config.h>' after each
'#include <autoconf.h>' since autoconf.h is only the for the
kernel config now. This is a temporarily solution, since we
currently don't have a way to tell which header files each file
is trying to include when it includes 'autoconf.h'

libsel4utils: check variable before dereferencing

libsel4utils: transition to new libelf API

libsel4utils: Handle GrantReply right

Minor build warning fixes

SELFOUR-1221: Support elf segment frame sharing

It is possible for the linker to generate segments that both overlap the
same frame. The elf loader now handles this by being aware that the
vspace reservation for its segment may overlap with other adjacent
segments.

It still tracks an individual reservation for each segment. But the
first of last frame of its segment may have been stored in the adjacent
segment's reservation. The frame gets given to the reservation with the
more permissive access rights. If the rights are the same, then the
frame is given to the segment with the lower address. When loading or
manipulating these loadable sections, regions need to be passed around
with their entire array so that the functions can look into adjacent
regions to use their reservations if necessary.

sel4utils: remove duplicate entry_point code

sel4utils: split loadable region counting function

Want to reuse internally without having to pull the elf pointer out of
the cpio archive every time.

libsel4utils: Explicitly cast integer to pointer type

SELFOUR-1083 Store name in test case and use C89, add elf_get_section

The test name is stored inside the testcase struct in order to make it
simpler to extract the test cases from sel4test-tests.

I changed the DEFINE_TEST_WITH_TYPE macro to use C89 instead of C99
style assignment because the domains.cxx (C++) tests would not compile
with C99-style assignment for strings.

I added sel4utils_elf_get_section() so that sel4test-driver can extract
the section containing test cases from sel4test-tests.

libsel4utils: Provide wrappers for retrieving ELF program headers

Fix licenses

Remove #ifdef guards for the existance of different libraries

These libraries are now all part of this same repository, and so they will always exist.
Guarding for them adds unnecessary complexity

SELFOUR-567: use seL4_CapRights_t

libsel4utils: Collapse some unnecessary forward declarations.

libsel4utils: Mark some strings as const.

all: s/LOG_*/ZF_LOG*

libsel4utils: fix typos.