dlopen() uses files, so do so as well.  Change DT_NEEDED handling to add the
path.

Needed for exception support.

Implemented strcat() accidentally.

Assumes no symlinks, cwd == /.

Should be pathname, not soname.

Forgotten.

If we looked up a symbol and it was undefined, ignore it.  This fixe a
problem with module binding to an undefined symbol in another.

This fixes vm initialization failing after system_reset because vm_created
was left set to 1.

It was portion of BSD license and taken from Linux/uapi.
A matching license clause is under the license directory.

* 'master' of github.com:/avikivity/osv: (28 commits)
  dlfcn: implement dlopen()
  elf: fail gracefully if a file is not found
  elf: return the elf_object just added from add()
  pthread: implement pthread_self()
  libc: implement sysconf(_SC_PHYS_PAGES)
  memory: count up total physical memory
  memory: set up free memory from the boot loader
  boot: set up cfi for premain environment
  boot: set up initial stack in allocated memory
  build: link in all .bss sections
  apic: add apic driver
  mutex: add with_lock() function
  scripts: run without SDL display
  main: auto-load gdb script
  sched: switch main thread stack from original stack
  main: add thread test case
  sched: add simple scheduler
  msr: add rdmsr()
  msr: add missing inline to wrmsr()
  elf: add accessor for tls segment info
  ...

Needed for dlopen() (also export the program object for the same reason).

Currently the free memory pool consists of a statically allocated buffer.
Replace it with a dynamic query of the amount of memory we actually booted with.

(currently limited to 1GB since we haven't mapped anything else yet).

Terminate the stack so gdb doesn't get confused trying to unwind it.