build: split CMakeLists

- Put add_custom_command into seperate ChiselBuild module. Otherwise
  final target cannot correctly depends on scala sources.

npc/csrc_nvboard/Flow/CMakeLists.txt

@@ -0,0 +1,23 @@
+include(ChiselBuild)
+
+add_custom_command(
+  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${TOPMODULE}/auto_bind.cpp
+  COMMAND auto_pin_bind ${CMAKE_SOURCE_DIR}/constr/${TOPMODULE}.nxdc ${CMAKE_CURRENT_BINARY_DIR}/${TOPMODULE}/auto_bind.cpp
+  DEPENDS ${CMAKE_SOURCE_DIR}/constr/${TOPMODULE}.nxdc
+)
+
+add_executable(V${TOPMODULE}_nvboard
+  ${CMAKE_CURRENT_BINARY_DIR}/${TOPMODULE}/auto_bind.cpp
+  main.cpp
+)
+
+verilate(V${TOPMODULE}_nvboard TRACE THREADS
+  TOP_MODULE ${TOPMODULE}
+  PREFIX V${TOPMODULE}
+  SOURCES ${CHISEL_OUTPUT_TOPMODULE}
+  INCLUDE_DIRS ${CHISEL_OUTPUT_DIR})
+
+target_include_directories(V${TOPMODULE}_nvboard PRIVATE ${NVBOARD_INCLUDE_DIR} ${SDL2_INCLUDE_DIRS})
+target_link_libraries(V${TOPMODULE}_nvboard PRIVATE ${NVBOARD_LIBRARY} SDL2::SDL2 SDL2_image::SDL2_image)
+
+install(TARGETS V${TOPMODULE}_nvboard)