remove exp10 from 3rdparty/rnnlm/rnnlmlib.cpp

[esdeboer]

3rdparty/rnnlm/rnnlmlib.cpp contains the function exp10 in some logging statements.

The exp10 function is not available on freeBSD, can you remove those logging lines, or change exp10 with pow(10.0, x)?

The muse project defined their own exp10 function if missing:
muse-sequencer/muse@348d849

[AdolfVonKleist]

If you create a pull request for this, I'm happy to merge it. I don't think this bit is really used much TBH. Unless you are actively using it you could also omit it from the compilation.

[esdeboer]

I created pull request #54 , the rmnllib only defined the exp10 for apple, not for the other systems not having it.