Use .dll.a file in th-dlls-minimal (#2216)

Author: hamishmack

test/th-dlls-minimal/default.nix

@@ -10,6 +10,10 @@ let
     cabalProjectLocal = builtins.readFile ../cabal.project.local;
     modules = [
      ({pkgs, ...}: {
+      packages.th-dlls-minimal.components.library.preBuild = ''
+        export ISERV_ARGS=-v
+        export PROSY_ARGS=-v
+      '';
       packages.test-lib.components.library.libs = mkForce [
         (pkgs.stdenv.mkDerivation {
           name = "test-clib";

test/th-dlls-minimal/test-clib/Makefile

@@ -5,12 +5,13 @@ test.a: test.o
 	$(AR) -rs test-clib.a test.o
 
 test.dll: test.o
-	$(CC) -o test-clib.dll -shared test.o
+	$(CC) -o test-clib-0.dll -shared test.o -Wl,--out-implib=test-clib.dll.a
 
 .PHONY: install
 install: test.a test.dll
 	mkdir $(out)/bin
 	mkdir $(out)/lib
-	mv test-clib.dll $(out)/bin
+	mv test-clib-0.dll $(out)/bin
+	mv test-clib.dll.a $(out)/bin
 	mv test-clib.a $(out)/lib