Here is Agner Fog's object file converter. It's an excellent tool to convert an object module to another format :
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, FMA and XOP instruction sets. Source code included (GPL).
http://agner.org/optimize/#objconv