Build on macOS produces ranlib warnings: "libretdec-bin2llvmir.a(FILE.cpp.o) has no symbols"

[s3rvac]

When building RetDec on macOS (OS 10.13, Apple LLVM version 9.0.0, Release build of RetDec), the make step for libretdec-bin2llvmir.a produces the following warnings:

[96%] Linking CXX static library libretdec-bin2llvmir.a
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_borland.cpp.o) has no symbols
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_intel.cpp.o) has no symbols
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_owatcom.cpp.o) has no symbols
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_borland.cpp.o) has no symbols
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_intel.cpp.o) has no symbols
XcodeDefault.xctoolchain/usr/bin/ranlib: file: libretdec-bin2llvmir.a(idioms_owatcom.cpp.o) has no symbols

We should investigate why is this happening, and possibly how to fix it so ranlib does not complain about it.

[Maroc-OS]

fix is here : #349