Add ELL to the book for bluez-5.57+

[Douglas R. Reno]

It looks like we need ELL (Embedded Linux Library) for BlueZ now, as of 5.57:

" Starting from BlueZ 5.57, it requires to use of ELL release 0.39 or later. "

It looks like a standard C/M/MI, but I'll have to verify that.

[Douglas R. Reno]

It looks like this package needs special kernel configuration.

   CONFIG_TIMERFD=y
   CONFIG_EVENTFD=y

   CONFIG_CRYPTO_USER_API=y
   CONFIG_CRYPTO_USER_API_HASH=y
   CONFIG_CRYPTO_MD5=y
   CONFIG_CRYPTO_SHA1=y

   CONFIG_KEY_DH_OPERATIONS=y

I pulled that out of the README

[Douglas R. Reno]

Xi mentioned that ELL is shipped in the BlueZ source tree as well. As I mentioned in IRC - why mention it as required if you're going to include it anyway? :)

I'll need to add kernel configuration to BlueZ's page though.

[Bruce Dubbs]

Milestone renamed