For llvm-objdump, add the option -private-header (without the trailing ’s’)

to only print the first private header.

Which for Mach-O files only prints the Mach header and not the subsequent load
commands.  Which is used by scripts to match what the darwin otool(1) with the
-h flag does without the -l flag.

For non-Mach-O files it has the same functionality as -private-headers (with
the trailing ’s’).

rdar://24158331

llvm-svn: 257548