PIC questions

[Michael Bushkov]

Hi,
I've got 2 questions about PIC.

1. NO_PIC variable. It is defined in several places across the system sources. 
As an example:
./lib/libcompat/Makefile:NO_PIC=
./lib/libdisk/Makefile:NO_PIC=
./lib/libstand/Makefile:NO_PIC=
./lib/liby/Makefile:NO_PIC=

What are the reasons for explicitly setting this variable in these libraries? 
I mean - as they are static, do we need to explicitly set NO_PIC there?

2. And theoretical question. Does every object that will be linked into the 
shared library should be built with PIC enabled?

-- 
With best regards,
Michael Bushkov