Fix invalid Mach-O object output from binutils' objcopy

objcopy-comp.sh

#!/bin/sh -e
 
# usage
#  objcopy-wrapper -I binary -O mach-o-x86-64 test test.o
 
# change path
~/binutils-2.25/binutils/objcopy "$@"
for last; do :; done
printf '\x00' | dd conv=notrunc of=$last bs=1 seek=11
 
symoff=$(otool -l $last | grep '\Wsymoff\W' | awk '{ print $2 }')
for sym in $(nm -ap $last | awk '{ print $(NF) }'); do
    case "$sym" in
        *_size)pp
            # does not link correctly for arch x86-64. `-O mach-o-i386` and `-arch i386` to compilers will fix.
            # http://stackoverflow.com/questions/31485714/mac-osx-ld-report-32-bit-rip-relative-reference-out-of-range-error-for-absolute
            printf '\x03\x00\x00\x00' | dd conv=notrunc of=$last bs=4 seek=$(echo "($symoff+4)/4" | bc)
            ;;
        *_end|*_start)
            printf '\x0f\x01\x00\x00' | dd conv=notrunc of=$last bs=4 seek=$(echo "($symoff+4)/4" | bc)
            ;;
        *)
            echo "Unexpected symbol pattern: $sym"
            exit 1
            ;;
    esac
    # change to 12 for i386
    symoff=$(echo "$symoff+16" | bc)
done