[MachO] Handle chained imports with addends

[bdash]

They show up in some macOS system executables.

[bdash]

I noticed this in a few executables, mostly for references to type info symbols from libc++. The unapplied imports prevent the RTTI analysis from handling these types.

For instance, in /usr/libexec/syspolicyd there are four std::exception subclasses with RTTI that references __ZTVN10__cxxabiv120__si_class_type_infoE + 0x10:

mrowe@dragon:~$ dyld_info -arch arm64e -fixups /usr/libexec/syspolicyd  | grep ' + '
__DATA_CONST    __const          0x100101B60      auth-bind  libc++/__ZTVN10__cxxabiv120__si_class_type_infoE + 0x10 (div=0x0000 ad=0 key=DA)
__DATA_CONST    __const          0x100101BB0      auth-bind  libc++/__ZTVN10__cxxabiv120__si_class_type_infoE + 0x10 (div=0x0000 ad=0 key=DA)
__DATA_CONST    __const          0x100101C00      auth-bind  libc++/__ZTVN10__cxxabiv120__si_class_type_infoE + 0x10 (div=0x0000 ad=0 key=DA)
__DATA_CONST    __const          0x100101C18      auth-bind  libc++/__ZTVN10__cxxabiv120__si_class_type_infoE + 0x10 (div=0x0000 ad=0 key=DA)