Calculi x

The use of /tmp in the ARPACK patch and config is probably not what EB wants, but it's the best solution I could find to use a full path during the build stage. 
have you tried `$(PWD)/libarpach_$(PLAT).a`? that should probably place `libarpack_$(PLAT).a` in the build dir?

it's a hack that can't be relied upon, but it's better than using `/tmp`, at least until we provide an environment variable for the build dir