The PT_GNU_PROPERTY is generated by a linker to describe the
.note.gnu.property section. The Linux kernel uses this program header to
locate the .note.gnu.property section.
It is described in "The Linux gABI extension"
Include support for llvm-readelf, llvm-readobj and the yaml reader and
writers.
Differential Revision: https://reviews.llvm.org/D70959
Peter Smith