Use linker-arguments only when linking
Use linker-arguments only when linking

Passing linker-arguments when only compiling will cause warnings with
Clang. This change fixes those.

Signed-off-by: Giel van Schijndel <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@mortis.eu>

wastholm/bitcoin,wastholm/bitcoin,wastholm/bitcoin,wastholm/bitcoin,wastholm/bitcoin,wastholm/bitcoin