runtime, targets: some WIP on wasm unknown in part from PR #3072

Signed-off-by: deadprogram <ron@hybridgroup.com>

src/runtime/runtime_tinygowasm_unknown.go

@@ -0,0 +1,50 @@
+//go:build wasm_unknown
+
+package runtime
+
+const (
+	stdout = 1
+)
+
+func putchar(c byte) {
+}
+
+func getchar() byte {
+	// dummy, TODO
+	return 0
+}
+
+func buffered() int {
+	// dummy, TODO
+	return 0
+}
+
+//go:linkname now time.now
+func now() (sec int64, nsec int32, mono int64) {
+	return 0, 0, 0
+}
+
+// Abort executes the wasm 'unreachable' instruction.
+func abort() {
+	trap()
+}
+
+//go:linkname syscall_Exit syscall.Exit
+func syscall_Exit(code int) {
+	//proc_exit(uint32(code))
+}
+
+// TinyGo does not yet support any form of parallelism on WebAssembly, so these
+// can be left empty.
+
+//go:linkname procPin sync/atomic.runtime_procPin
+func procPin() {
+}
+
+//go:linkname procUnpin sync/atomic.runtime_procUnpin
+func procUnpin() {
+}
+
+func hardwareRand() (n uint64, ok bool) {
+	return 0, false
+}