matrix decompositions fails on Max os X 10.2

[Brian Gough]

Erik Ø. Sørensen writes:
 > Matrix decompositions seem to fail:
 > 
 > PASS:   bidiag_decomp m(5,3)
 > (  9,  7)[0,0]:    1.00000095367431574                        1

Try compiling that directory without optimisation, to see if it is
compiler-related.  I think it is likely to be, since the code works on
other platforms.