ports/fuseiso/README.nacl

Original fuseiso is a standalone app, however for naclport,
we chagned it to a library so that we can use it in other app.

Major Changes for port fuseiso:
1. added 'nacl_fuseiso_lib_init' and removed 'main' function in fuseiso.c.
 
2. disabled the check for mnttab(fuseiso.c).

3. disabled isofs_real_statfs, the parameters we have in nacl_io is statvfs,
   but in fuseiso, it requires statfs, also since we nacl_io currently 
   doesn't support statfs(more details see nacl_io/fuse.h in nacl_sdk).

4. in currenl newlib, we don't have "bswap_16", using "__byte_swap_16" 
   from sys/endian.h instead.

5. created a seperate Makefile.in for fuseisolib.

Some sample code to test this lib(newlib version):

//fusefoo.c

#include <fuseiso_lib.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

int main(int argc, char* argv[]) {
  char* path = "<YOUR ISO PATH>";
  char* mount_point = "/foo";
  char* fs_name = "fuseiso_fs";
  mkdir(mount_point, 0777);
  nacl_fuseiso_lib_init(path, mount_point, fs_name);

  char buffer[1024];
  int fd = open("/foo/<PATH_IN_ISO>", O_RDONLY);

  read(fd, &buffer,1024);
  printf("%s\n", buffer);
  close(fd);
  return 0;
}

// copy and paste following command to complie and link, 
// you might need install (ncurses nacl-spawn glib glibc-compat) first.

NACLSDKPATH= <nacl_sdk home path e.g. /home/foo/nacl_sdk/pepper_canary> 

$NACLSDKPATH/toolchain/linux_x86_newlib/bin/x86_64-nacl-gcc  fusefoo.c \
  -DHAVE_CONFIG_H -I. -I. -I.. -I$NACLSDKPATH/include/nacl_io \
  -I$NACLSDKPATH/include -I$NACLSDKPATH/ports/include  \
  -I$NACLSDKPATH/toolchain/linux_x86_newlib/x86_64-nacl/usr/include \
  -Wall -DNDEBUG -O2 -c

$NACLSDKPATH/toolchain/linux_x86_newlib/bin/x86_64-nacl-gcc \
  -I$NACLSDKPATH/include -L$NACLSDKPATH/lib/newlib_x86_64/Release \
  -L$NACLSDKPATH/toolchain/linux_x86_newlib/x86_64-nacl/usr/lib \
  -L$NACLSDKPATH/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib \
  -o fusefoo_newlib.nexe fusefoo.o  -Wl,--undefined=PSUserMainGet \
  -Xlinker -uPSUserMainGet -lcli_main -lnacl_spawn -lppapi_simple \
  -lnacl_io -lppapi -lfuseiso -lstdc++ -lncurses -lglib-2.0 -lz -lintl

Should be able to get a fusefoo_newlib.nexe after complie and link.
Copy fusefoo_newlib.nexe and the iso file to devenv to test it.