The binary layout of prstatus and prpsinfo was wrong.
Some of the member variables where not aligned properly
and others where with a wrong type (e.g. the time related
stuff in prstatus).
I used the structs defined in bfd in binutils to see what the layout
of the elf-core format in these section is.
Note: those structures are only for x86 64 bit elf-core files
This shouldn't have any impact on the functionality, because
lldb actually uses only a few of the member variables of those structs
and they are with a correct type and alignment.
I found this while trying to add/fix the support for
i386 core files (https://llvm.org/bugs/show_bug.cgi?id=26947)