Comment # 3 on bug 1115034 from Tom de Vries

The solution for the compilation error with gcc-PIE not installed is to teach
gnatlink to include libgnat_pic.a for -pie.

Assuming that's fixed, the solution for the compilation error with gcc-PIE
installed could be to have a libgnat_default.a symlink,  which points to:
- libgnat.a, when gcc-PIE is not installed
- libgnat_pic.a, when gcc-PIE is installed.

Then update gnatlink to use libgnat_default.a by default, and libgnat.a for
-no-pie.