On cygwin with dynamic linkage the compiler flag "-O0" seems to produce
a corrupt debug library [1].
As a workaround I've replace "-O0" with "-O1" in the current development
version. This is not elegant, but at least mitigates the problem...
So you can use the current development version, or alternatively change
-O0 to -O1 by hand in the build system of deal.II 7.3.0.
Best,
Matthias
[1]
http://code.google.com/p/dealii/issues/detail?id=7&can=1