[FIX] don't detect openmp on clang
[FIX] don't detect openmp on clang

hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,ktrappe/seqan,bestrauc/seqan,xenigmax/seqan,ktrappe/seqan,bestrauc/seqan,bestrauc/seqan,hannespetur/SeqAnHTS,xenigmax/seqan,hannespetur/SeqAnHTS,xenigmax/seqan,ktrappe/seqan,bestrauc/seqan,bestrauc/seqan,ktrappe/seqan,xenigmax/seqan,ktrappe/seqan,ktrappe/seqan,xenigmax/seqan,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,hannespetur/SeqAnHTS,ktrappe/seqan,xenigmax/seqan,bestrauc/seqan,ktrappe/seqan,xenigmax/seqan,bestrauc/seqan,bestrauc/seqan,ktrappe/seqan,xenigmax/seqan,hannespetur/SeqAnHTS