code in support to use SYSCONFDIR

[andy5995]

SYSCONFDIR can be passed to bric during compiling. it defaults to /usr/local/etc and can be changed during compile-time by using a ../configure option.

It's coded in as a define directive at the time of build, see

https://github.com/shnupta/bric/blob/a8d8e4b70e0f8c2c43e51a163933014a7dd22b55/Makefile.am#L31

Bric should look for .bricrc (see #145) first in the user's home directory, and if not found, look in SYSCONFDIR for bricrc (no dot preceding the filename).