PIE executables should be added to ELF

LSB doesn't currently support position-independent executables (PIE) as the
combination of flags indicating executable and shared object together is not
listed. There's a pending bug on a failing appbat app (see bug 1382). I need
to check if there's been any proposal to update the ABI that I haven't pulled
over.

Here's a reference that says something about PIE as an example.

http://www.linuxfromscratch.org/hlfs/view/unstable/glibc-2.6/chapter02/pie.html

There are some details that would need documenting but the biggest issue is, I
think, allowing executables with e_type=ET_DYN