Hi guix-devel,

this is a patch to add the GCTP library. It seems the library is no 
longer maintained separately (“official” sources are gone), so this 
package downloads the HDF-EOS5 source, which contains GCTP, and 
patches the build to only build and install GCTP. (I'm packaging 
HDF-EOS5 later on)

It's not very elegant... An alternative solution would be to get the 
source package from, e.g. Debian, and build that (might involve less 
patching).

Thomas