Avoid Fortran warnings and fix data package lookup
When trying to build Gauss locally using the LbDevTools toolchain (and Gaudi/master, if that matters), I had to fix the data package lookup.
I also fixed the 100s of warnings coming from Fortran (at least locally), such as
f951: Warning: Nonexistent include directory 'build/include' [-Wmissing-include-dirs]