This is what I did to get the AMD Catalyst™ 14.9 and 14.12 Proprietary Linux x86 Display Driver, available at http://support.amd.com/en-us/download/desktop?os=Linux%20x86_64 to work with Linux 3.17.2 to 3.19.3 in Fedora 20. There's a lot of other mucking about to get the driver running the first time, but it basically boils down to not running GNOME or using GDM. A good starting point for how to sort all of this out is at https://bluehatrecord.wordpress.com/2014/11/13/installing-the-proprietary-amd-catalyst-14-9-fglrx-driver-on-fedora-20-with-kernel-3-17/.
Disclaimer: This works for me, but I take no responsibility if following these instructions melt your graphics card or cause any other unfortunate events.
$ ./amd-driver-installer-14.301.1001-x86.x86_64.run --extract
$ cd <extracted_dir>
$ patch -p1 < <path/to/3.17-3.19.patch>
For 14.9:
$ sudo ./ati-installer.sh 14.301.1001 --install
For 14.12:
$ sudo ./ati-installer.sh 14.501.1003 --install
It doesn't really seem to matter too much what the second argument is, but I suspect that it's stored in a version file somewhere, so it's probably good to give it the right argument.
Updated the gist to cover all kernel revisions between 3.17 to 3.19. Maybe I should be proactive and give it a go with 4.0 while I'm at it 😃