Fix implicit declaration of ioctl on Solaris
bitops.c/redisPopcount: little optimization in loop
bitops.c/bitopCommand: skip short minlen for FAST PATH
Check that tcp-backlog is matched by /proc/sys/net/core/somaxconn.
Silence _BSD_SOURCE warnings in glibc 2.20 and forward

See https://sourceware.org/glibc/wiki/Release/2.20#Packaging_Changes
Simplify lua_cmsgpack macro and fix build on old Linux distros.

Thanks to @badboy for the help in checking the build after the fix.
getting pid fixes

```sh
$ ~ pidof redis-server
# nothing

$ ~ ps aux | grep [r]edis
redis      593  0.0  0.0  36900  5564 ?        Ssl  Dec02   1:37 /usr/bin/redis-server 127.0.0.1:6379
klay     15927  0.0  0.0  16772  6068 pts/6    S+   13:58   0:00 redis-cli

$ ~ uname -a
Linux edge 3.17.4-1-ARCH #1 SMP PREEMPT Fri Nov 21 21:14:42 CET 2014 x86_64 GNU/Linux
```
Update whatisdoing.sh

Improved getting pid
sparkline.c: mov label-ini into the AddSample Function
sparkline.c: AddSample skip Empty label
Only ignore sigpipe in interactive mode

This allows shell pipes to correctly end redis-cli.

Ref #2066
Merge pull request #2200 from badboy/iss2066-additional

Only ignore sigpipe in interactive mode
Merge pull request #2197 from sunheehnus/sparkline

sparkline.c: mov label-ini into the AddSample Function
Merge pull request #2192 from sergeyklay/patch-1

getting pid fixes
Mark whatisdoing.sh as deprecated in top-comment.
Merge pull request #2189 from jbergstroem/glibc_220_default_warn

Silence _BSD_SOURCE warnings in glibc 2.20 and forward
Merge pull request #2179 from sunheehnus/bitops-read

bitops.c/redisPopcount: optimization in loop
Merge pull request #2177 from badboy/solaris-ioctl-warn-fix

Fix implicit declaration of ioctl on Solaris
Include stropts only if __sun is defined.
Merge pull request #1 from antirez/unstable

update