Use xorriso to generate iso if possible

On some Linux distributions (e.g. Debian 9) genisoimage does not
support -e option we need. Use xorriso to solve that.
1 file changed
tree: c5e25e4ba08216c770251ef1b591f08ee71f84f2
  1. boot/
  2. editdisklbl/
  3. initrd/
  4. install/
  5. rpm/
  6. Android.mk
  7. CleanSpec.mk