The -fPIE option is now accepted when using GCC 4, which means it
is available for backward compatibility for clients using
CMake 2.8.11 or older which makes use of the
POSITION_INDEPENDENT_CODE feature.

Conditionally use that feature for old versions of cmake with
GCC 4. Restore the tests for those versions, and clarify the
situation in the ChangeLog.

Change-Id: I5a06b155dda7db559d86841a2b34fd8ed95acbd0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>