native runner

platformio.ini

@@ -0,0 +1,18 @@
+; PlatformIO project manifest.
+;
+; This repo is primarily a *library* (see library.json / library.properties),
+; but this manifest also defines a host "native" environment so the portable C
+; core can be built and unit-tested on your computer with no hardware:
+;
+;     pio test -e native
+;
+; It compiles only the portable C core (src/*.c) plus the test in test/. The C++
+; Arduino wrapper (src/*.cpp) is excluded here because it needs <Arduino.h>,
+; which only exists in a real Arduino/PlatformIO board build.
+
+[env:native]
+platform = native
+test_framework = custom
+test_build_src = yes
+build_src_filter = +<*.c> -<*.cpp>
+build_flags = -std=c99 -Wall -Wextra -Isrc