Agner Fog's Object File Converter

This utility can be used for converting object files between COFF/PE,
OMF, ELF and Mach-O formats for all 32-bit and 64-bit x86 platforms.
Can modify symbol names in object files. Can build, modify and convert
function libraries across platforms. Can dump object files and
executable files. Also includes a very good disassembler supporting the
SSE4, AVX, AVX2, AVX512, FMA3, FMA4, XOP and Knights Corner instruction
sets. Source code included (GPL).

WWW: https://www.agner.org/optimize/

Note: Agner likes to update the distribution file without bumping the
version number.  Whenever I notice that, I upload the new file with an
_... suffix to keep the check sums of the files stable.