RHEL8 is currently running python-3.6 (according to google). So, it might work. But I would not be surprised to find that an adjustment or two might be needed for the older packages in RHEL8. The installation steps should be the same as fedora (RHEL is based on fedora) found in the README. In particular you will want to check the list of "Requires" packages found in the config/gfe.spec file and make sure they are installed before attempting the build.
The HLS is there when I configure 1.17.1 for the LCH site. It won't run without the patch that was recently checked into the tree. But it is there. What version of the gfe are you using?
The HLS works for me with site LOX. However you will need the patch I just checked into git. The next release will have this fix for the HLS.
Not all sites are configured to have all products. The gfe uses information in the etc/afos2awips.txt file to see if a given site has a given product. For example BOU and CAE don't have an HLS product. But LOX does. I usually test with the default BOU site so the HLS is not up front in my testing. But I did just do an install with site=LOX and the HLS is there. GenerateCyclone requires products from the national centers. There is currently no way to ingest these products. So, It is expected that...
Your build is still not sucessful so the make install target is failing. What errror do you get with just plain 'make'?
gd-devel is in the config/gfe.spec file. You will need to make sure that every package mentioned in a Requires line there is installed.
Install the gd-devel package. It looks like I missed that in gfe.spec file. I'll add it there too.
Attached is the fixed linkHeaders script. It will also be checked into git. You should be able to copy it over the one in your tree and then still use the testing directory name.