gcc-4.3.3: add a patch to link with the math lib to get copysignal

Conditionally apply the following patch by Bernhard Reutner-Fischer which
solves a link error on powerpc (with softfloat or multilib) when using
a shared libgcc_s.

See: http://gcc.gnu.org/ml/gcc-patches/2008-10/msg00237.html
http://www.nabble.com/PPC-won't-build-with-soft-float-td22772110.html



Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>