llvm-readelf fails to report > 65535 segments

[emaste]

From FreeBSD bug 285547 a regression test started failing after we switched to LLVM's binutils replacements.

The test creates an ELF core file with more than 65535 segments (test source code). llvm-readelf reports 65535 program headers.

GNU readelf:

$ /usr/local/bin/readelf -h ./coredump_phnum_help.core
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 09 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - FreeBSD
  ABI Version:                       0
  Type:                              CORE (Core file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          64 (bytes into file)
  Start of section headers:          3726864 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         65535 (66550)
  Size of section headers:           64 (bytes)
  Number of section headers:         1
  Section header string table index: 0

llvm-readelf:

$ readelf -h ./coredump_phnum_help.core
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 09 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - FreeBSD
  ABI Version:                       0
  Type:                              CORE (Core file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          64 (bytes into file)
  Start of section headers:          3726864 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         65535
  Size of section headers:           64 (bytes)
  Number of section headers:         1
  Section header string table index: 0

Support added to FreeBSD's copy of ELF Tool Chain: freebsd/freebsd-src@714935b