Proprietary and bloated yes, but I believe both Xilinx and Altera both have software available for Linux, or am I wrong? At least I used Altera's suite on Linux once for a pilot project.
First result on google says quartus uses its own libcurl which is broken and you should copy the OS libcurl to /opt/altera/quartus/lin64/lib/whatever. Lots of issues like this.