tests for functions used in NCEPLIBS-ip

[edwardhartnett]

When I take NCEPLIBS-sp out of the NCEPLIBS-ip build, I get the following errors:

/usr/bin/ld: /home/ed/NCEPLIBS-ip/src/polates4.f90:263: undefined reference to `sptrunm_'
/usr/bin/ld: /home/ed/NCEPLIBS-ip/src/polates4.f90:270: undefined reference to `sptrung_'
/usr/bin/ld: /home/ed/NCEPLIBS-ip/src/polates4.f90:240: undefined reference to `sptruns_'
/usr/bin/ld: ../src/libip_4.a(gdswzd04_mod.f90.o): in function `__gdswzd04_mod_MOD_gdswzd04':
/home/ed/NCEPLIBS-ip/src/gdswzd04_mod.f90:177: undefined reference to `splat_'

So these functions would be a good place to start testing.