Build improvements and warning fixes

[Guillem Jover]

I've cleaned up some of the stuff I've had on my local tree for some
time now. I'll try to clean up the rest.

[PATCH 01/17] Add a .gitignore file
[PATCH 02/17] Enable silent builds by default if available

I'm resending these two, as they seem to have fallen through the cracks.

[PATCH 03/17] Use AC_LANG_SOURCE inside AC_LANG_CONFTEST to fix
[PATCH 04/17] Disable compiler built-in symbols to avoid namespace
[PATCH 05/17] Do not take obsolete and unused bcopy and bzero from
[PATCH 06/17] Add prototypes for locore functions
[PATCH 07/17] Add prototype for log function
[PATCH 08/17] Add prototype for free_skbuffs function
[PATCH 09/17] Add header for printf prototype
[PATCH 10/17] Remove ident tags producing preprocessor warnings
[PATCH 12/17] Disable unused variables
[PATCH 13/17] Match signedness of char pointer comparisons and
[PATCH 14/17] Fix initialization from incompatible pointer type
[PATCH 15/17] Move cdrom_sleep() definition where it belongs
[PATCH 16/17] Always initialize A and X variables in BPF code

These seem pretty stright forward to me.

[PATCH 11/17] Remove unused variables

This one had the kr removal already which is included in Fridolín's
patch, I can resubmit with that removed.

[PATCH 17/17] Initialize the new map entry when it's a projected

This one seems correct at first sight, but I'm actually surprised this
has not caused many failures in the past...

regards,
guillem