Fixes necessary for e2fsprogs to work using the diet libc.

Fixes necessary for e2fsprogs to work using the diet libc.

- Renamed linux/list.h to be linux/linked_list.h to work around a
  problem caused by diet libc insistence to search the kernel
  header files ahead of all other files in the include path,
  including the user specified include files.

- Worked around a bug in diet libc which core dumps when using
  putc with stderr by using fputs instead.  As a bonus, this
  also shaved a few bytes off of com_err.o.

- Fixed a real bug in debugfs which was detected because diet libc
  was more sensitive than glibc when incorrectly using fclose()
  where pclose() is required.