Fix to missing VTK directory

EnhancedSolver/3D-seq/Makefile

@@ -29,7 +29,7 @@ ${TARGET}: $(BUILD_DIR) $(OBJ)
 	$(info ===>  LINKING  $(TARGET))
 	$(Q)${LINKER} ${LFLAGS} -o $(TARGET) $(OBJ) $(LIBS)
 
-$(BUILD_DIR)/%.o:  %.c $(MAKE_DIR)/include_$(TAG).mk $(MAKE_DIR)/config.mk
+$(BUILD_DIR)/%.o:  %.c $(MAKE_DIR)/include_$(TAG).mk $(MAKE_DIR)/config.mk vis_dir
 	$(info ===>  COMPILE  $@)
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 	$(Q)$(GCC) $(CPPFLAGS) -MT $(@:.d=.o) -MM  $< > $(BUILD_DIR)/$*.d
@@ -38,7 +38,7 @@ $(BUILD_DIR)/%.s:  %.c
 	$(info ===>  GENERATE ASM  $@)
 	$(CC) -S $(CPPFLAGS) $(CFLAGS) $< -o $@
 
-.PHONY: clean distclean tags info asm format
+.PHONY: clean distclean tags info asm format vis_dir
 
 vis:
 	$(info ===>  GENERATE VISUALIZATION)
@@ -85,4 +85,7 @@ format:
 $(BUILD_DIR):
 	@mkdir $(BUILD_DIR)
 
+vis_dir:
+	@mkdir -p vtk_files
+
 -include $(OBJ:.o=.d)