change how the C smoke test program builds

src/CMakeLists.txt

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(protodemo C CXX)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 20)
+
+add_compile_options(-Wall -g3 -Og)
+add_executable(protodemo
+    protodemo.cpp
+    piolib/piolib.c
+    piolib/pio_rp1.c
+)
+
+add_custom_command(
+    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/protomatter.pio.h
+    COMMAND python ${CMAKE_CURRENT_SOURCE_DIR}/assemble.py ${CMAKE_CURRENT_SOURCE_DIR}/protomatter.pio ${CMAKE_CURRENT_BINARY_DIR}/protomatter.pio.h
+    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/assemble.py ${CMAKE_CURRENT_SOURCE_DIR}/protomatter.pio
+)
+
+target_include_directories(protodemo PRIVATE include piolib/include)

src/Makefile

@@ -1,7 +0,0 @@
-protodemo: protodemo.c piolib/*.c include/piomatter/*.h include/piomatter/protomatter.pio.h Makefile
-	g++ -std=c++20 -O3 -ggdb -x c++ -Iinclude -Ipiolib/include -o $@ $(filter %.c, $^) -Wno-narrowing
-
-matrixmap.h:
-
-include/piomatter/protomatter.pio.h: protomatter.pio assemble.py
-	python assemble.py $< $@