Mac OS ranlib warning

When compiling on MacOs the following warning appears:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: libpetrack_core.a(mocs_compilation.cpp.o) has no symbols
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: libpetrack_core.a(mocs_compilation.cpp.o) has no symbols

added low tooling labels

added To Do label

assigned to @t.schroedter and unassigned @d.kilic

closed with merge request !91 (merged)

mentioned in commit 109786db

Fixed, can stay closed.