Removed unnecessary linker flags when building the Python extension
Removed unnecessary linker flags when building the Python extension

This resolves errors when compiling on OS X when the full set of
cross-compilers (e.g. for ppc) are not present, as well as several
warnings even when they are.


imitrichev/cantera,Heathckliff/cantera,Heathckliff/cantera,imitrichev/cantera,imitrichev/cantera,Heathckliff/cantera,Heathckliff/cantera,imitrichev/cantera,Heathckliff/cantera,imitrichev/cantera,Heathckliff/cantera,imitrichev/cantera