diff --git a/Makefile b/Makefile
index 234b8a2c88..0c426ca5bc 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@ LD = ld
 
 EXECUTABLE = factor
 CONSOLE_EXECUTABLE = factor-console
+TEST_LIBRARY = factor-ffi-test
 VERSION = 0.92
 
 IMAGE = factor.image
@@ -35,7 +36,6 @@ DLL_OBJS = $(PLAF_DLL_OBJS) \
 	vm/debug.o \
 	vm/errors.o \
 	vm/factor.o \
-	vm/ffi_test.o \
 	vm/image.o \
 	vm/io.o \
 	vm/math.o \
@@ -48,6 +48,8 @@ DLL_OBJS = $(PLAF_DLL_OBJS) \
 
 EXE_OBJS = $(PLAF_EXE_OBJS)
 
+TEST_OBJS = vm/ffi_test.o
+
 default:
 	$(MAKE) `./build-support/factor.sh make-target`
 
@@ -81,60 +83,60 @@ help:
 	@echo "X11=1  force link with X11 libraries instead of Cocoa (only on Mac OS X)"
 
 openbsd-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.openbsd.x86.32
 
 openbsd-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.openbsd.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.openbsd.x86.64
 
 freebsd-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.freebsd.x86.32
 
 freebsd-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.freebsd.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.freebsd.x86.64
 
 netbsd-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.netbsd.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.netbsd.x86.32
 
 netbsd-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.netbsd.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.netbsd.x86.64
 
 macosx-ppc:
-	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.ppc
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) macosx.app CONFIG=vm/Config.macosx.ppc
 
 macosx-x86-32:
-	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) macosx.app CONFIG=vm/Config.macosx.x86.32
 
 macosx-x86-64:
-	$(MAKE) $(EXECUTABLE) macosx.app CONFIG=vm/Config.macosx.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) macosx.app CONFIG=vm/Config.macosx.x86.64
 
 linux-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.linux.x86.32
 
 linux-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.linux.x86.64
 
 linux-ppc:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.ppc
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.linux.ppc
 
 linux-arm:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.linux.arm
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.linux.arm
 
 solaris-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.solaris.x86.32
 
 solaris-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.solaris.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.solaris.x86.64
 
 winnt-x86-32:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.nt.x86.32
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.windows.nt.x86.32
 	$(MAKE) $(CONSOLE_EXECUTABLE) CONFIG=vm/Config.windows.nt.x86.32
 
 winnt-x86-64:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.nt.x86.64
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.windows.nt.x86.64
 	$(MAKE) $(CONSOLE_EXECUTABLE) CONFIG=vm/Config.windows.nt.x86.64
 
 wince-arm:
-	$(MAKE) $(EXECUTABLE) CONFIG=vm/Config.windows.ce.arm
+	$(MAKE) $(EXECUTABLE) $(TEST_LIBRARY) CONFIG=vm/Config.windows.ce.arm
 
 macosx.app: factor
 	mkdir -p $(BUNDLE)/Contents/MacOS
@@ -157,6 +159,9 @@ factor-console: $(DLL_OBJS) $(EXE_OBJS)
 	$(CC) $(LIBS) $(LIBPATH) -L. $(LINK_WITH_ENGINE) \
 		$(CFLAGS) $(CFLAGS_CONSOLE) -o factor$(EXE_SUFFIX)$(CONSOLE_EXTENSION) $(EXE_OBJS)
 
+factor-ffi-test: $(TEST_OBJS)
+	$(CC) $(LIBPATH) $(CFLAGS) $(SHARED_FLAG) -o libfactor-ffi-test$(DLL_EXTENSION) $(TEST_OBJS)
+
 clean:
 	rm -f vm/*.o
 	rm -f factor*.dll libfactor.{a,so,dylib}
diff --git a/vm/Config.macosx b/vm/Config.macosx
index 42334a0524..6655d548b7 100644
--- a/vm/Config.macosx
+++ b/vm/Config.macosx
@@ -5,6 +5,8 @@ PLAF_DLL_OBJS += vm/os-macosx.o vm/mach_signal.o
 
 DLL_EXTENSION = .dylib
 
+SHARED_FLAG = -dynamiclib
+
 ifdef X11
 	LIBS = -lm -framework Cocoa -L/opt/local/lib $(X11_UI_LIBS) -Wl,-dylib_file,/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib:/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib
 else
diff --git a/vm/Config.unix b/vm/Config.unix
index e8cb877249..8f2f140247 100644
--- a/vm/Config.unix
+++ b/vm/Config.unix
@@ -6,6 +6,7 @@ EXE_SUFFIX =
 DLL_PREFIX = lib
 DLL_EXTENSION = .a
 # DLL_EXTENSION = .so
+SHARED_FLAG = -shared
 
 PLAF_DLL_OBJS = vm/os-unix.o
 PLAF_EXE_OBJS += vm/main-unix.o
diff --git a/vm/Config.windows b/vm/Config.windows
index 45d2f0cb98..75452a9bb4 100644
--- a/vm/Config.windows
+++ b/vm/Config.windows
@@ -1,6 +1,7 @@
 CFLAGS += -DWINDOWS -mno-cygwin
 LIBS = -lm
 PLAF_DLL_OBJS += vm/os-windows.o
+SHARED_FLAG = -shared
 EXE_EXTENSION=.exe
 CONSOLE_EXTENSION=.com
 DLL_EXTENSION=.dll