update stack file

Author: prolic

package.yaml

@@ -29,6 +29,10 @@ library:
   source-dirs: src
   pkg-config-dependencies:
     - libsecp256k1
+  hs-source-dirs:
+    src
+  c-sources:
+    cbits/hs_secp256k1_shim.c
 tests:
   spec:
     main: Main.hs