Combine CPython wrapper into a single target

I don't know why I thought it was a good idea to split that into two
parts. Just do it with one command.
Interestingly, the old way worked perfectly fine on arch, but produced
an empty .so on debian. Huh!

lib.mk

@@ -32,9 +32,6 @@ $(LIB): $(OBJS_lib) $(OBJDIR_lib)
 $(BIN_lib): $(LIB) $(OBJS_driver) $(OBJDIR_driver)
 	@echo "LD $@"
 	@$(CC) $(CFLAGS) $(OBJS_driver) $(LIB) -o $@ $(LDFLAGS)
-wrappers/cray.o: wrappers/cray.c
-	@echo "CC -fPIC $@"
-	@$(CC) `pkg-config --cflags python3` $(CFLAGS) -o wrappers/cray.o -shared -fPIC wrappers/cray.c
-wrappers/cray.so: $(LIB) wrappers/cray.o
+wrappers/cray.so: $(LIB) wrappers/cray.c
 	@echo "Building Python module"
-	@$(CC) -shared -fPIC wrappers/cray.o $(LIB) -o $@
+	@$(CC) -shared $(CFLAGS) -fPIC `pkg-config --cflags python3` wrappers/cray.c $(LIB) -o $@