Mach-O: Add Mach-O parser for OS X and iOS.

This parser also supports fat binaries which archive multiple
Mach-O binaries.
Mach-O: Use Mach-O parser to extract install names instead of otool.

This has much better performance than calling "otool" or "xcrun -r otool"
to extract install names for rpath support.

Fixes bug #15178.
Merge topic 'macho-parser'

c294a115 Mach-O: Use Mach-O parser to extract install names instead of otool.
e42da307 Mach-O: Add Mach-O parser for OS X and iOS.