gcc runtime: specify license on a per package basis

gcc runtime: specify license on a per package basis

It can be alarming to attempt to exclude GPLv3 from an
image but find that libstdc++ and libgcc still show it.
We indicate the license for each package to show libraries
that really are just GCC-3.0-with-GCC-exception.

Signed-off-by: Joe Slater <jslater@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>