Cannot build programs with `-gc=none/leaking` on raspberry pi pico

Latest dev branch. Cannot build a simple program on pico nor pico2 ``` tinygo build -target=pico2 -gc=none . # runtime /home/pato/Documents/src/tg/tinygo/src/runtime/runtime_rp2.go:235:2: undefined: gcScanState /home/pato/Documents/src/tg/tinygo/src/runtime/runtime_rp2.go:245:2: undefined: scanCurrentStack /home/pato/Documents/src/tg/tinygo/src/runtime/runtime_rp2.go:252:2: undefined: gcScanState /home/pato/Documents/src/tg/tinygo/src/runtime/runtime_rp2.go:262:2: undefined: gcScanState ```