rig: could not find native static library `ssl`, perhaps an -L flag is missing?

Hi Gábor,

Thanks for this really nice piece of software.

I am trying to install rig from source on Arch Linux with:

cd rig-0.5.2/
make linux

but I’m getting this error:

(...)
   Compiling native-tls v0.2.10
error: could not find native static library `ssl`, perhaps an -L flag is missing?

error: could not compile `openssl-sys` due to previous error
warning: build failed, waiting for other jobs to finish...
make: *** [Makefile:63: target/release/rig] Error 101

Can you help?