vlib: add a wasm module, implementing a pure V webassembly seralisation library (#17909)

vlib/wasm/functions.v

@@ -0,0 +1,28 @@
+module wasm
+
+struct ImportCallPatch {
+	mod  string
+	name string
+	pos  int
+}
+
+struct FunctionCallPatch {
+	name string
+	pos  int
+}
+
+type CallPatch = FunctionCallPatch | ImportCallPatch
+
+struct Function {
+	tidx int
+	idx  int
+mut:
+	call_patches []CallPatch
+	label        int
+	export       bool
+	mod          &Module
+	code         []u8
+	locals       []ValType
+pub:
+	name string
+}