[FIX] gcc8 warning in test_stream_lexical_cast.h [-Wcatch-value=]
[FIX] gcc8 warning in test_stream_lexical_cast.h [-Wcatch-value=]

/seqan-src/tests/stream/test_stream_lexical_cast.h:235:5: warning: catching polymorphic type ‘struct seqan::BadLexicalCast’ by value [-Wcatch-value=]
     catch (BadLexicalCast)
     ^~~~~

xenigmax/seqan,xenigmax/seqan,xenigmax/seqan,xenigmax/seqan,xenigmax/seqan,xenigmax/seqan,xenigmax/seqan,xenigmax/seqan