set ffilib path

Author: jordy25519

Diff for: .github/workflows/build.yml

@@ -54,6 +54,7 @@ jobs:
           DRIFT_GATEWAY_KEY: ${{ secrets.DRIFT_GATEWAY_KEY }}
           TEST_DELEGATED_SIGNER: ${{ secrets.TEST_DELEGATED_SIGNER }}
           TEST_RPC_ENDPOINT: ${{ secrets.DEVNET_RPC_ENDPOINT }}
+          CARGO_DRIFT_FFI_PATH: /usr/lib
         # --test-threads, limit parallelism to prevent hitting RPC rate-limits
         run: |
           cargo -V