Add a demo code for PicoCalc

Code/picocalc_helloworld/lcdspi/CMakeLists.txt

@@ -0,0 +1,20 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+
+project(lcdspi
+        VERSION 0.0.1
+        DESCRIPTION "lcdspi for rp2040."
+        )
+
+add_library(lcdspi INTERFACE)
+
+target_sources(lcdspi INTERFACE
+        lcdspi.c
+        )
+
+target_link_libraries(lcdspi INTERFACE  pico_stdlib hardware_spi)
+
+target_include_directories(lcdspi INTERFACE ${CMAKE_CURRENT_LIST_DIR})