build iccdump with ninja, warnings fixes

  - fatal() doesn't return... mark it that way
  - explicit unsigned -> signed in signature_to_string()
  - explicit signed -> unsigned result of ftell()
  - explicit float -> double for printf()

Change-Id: I2fe26de9f3e866a1f71d9e2a58f75ac0dff354c0
Reviewed-on: https://skia-review.googlesource.com/94780
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed