feat: implement baremetal GC

fix: pthread gc

fix: xiao-esp32c3 symbol

refactor: use clite memset instead of linking

fix: stack top symbol

runtime/internal/clite/bdwgc/bdwgc.go

@@ -26,6 +26,11 @@ const (
 	LLGoPackage = "link: $(pkg-config --libs bdw-gc); -lgc"
 )
 
+//export initGC
+func initGC() {
+	Init()
+}
+
 // -----------------------------------------------------------------------------
 
 //go:linkname Init C.GC_init

runtime/internal/clite/pthread/pthread_gc.go

@@ -1,5 +1,4 @@
-//go:build !nogc
-// +build !nogc
+//go:build !nogc && !baremetal
 
 /*
  * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.

runtime/internal/clite/pthread/pthread_nogc.go

@@ -1,5 +1,4 @@
-//go:build nogc
-// +build nogc
+//go:build nogc || baremetal
 
 /*
  * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.