Implement source debugging for interpreter and AOT (#769)

Implement source debugging feature for classic interpreter and AOT:
- use `cmake -DWAMR_BUILD_DEBUG_INTERP=1` to enable interpreter debugging
- use `cmake -DWAMR_BUILD_DEBUG_AOT=1` to enable AOT debugging

See doc/source_debugging.md for more details.

core/iwasm/compilation/aot.h

@@ -21,6 +21,10 @@ typedef InitializerExpression AOTInitExpr;
 typedef WASMType AOTFuncType;
 typedef WASMExport AOTExport;
 
+#if WASM_ENABLE_DEBUG_AOT != 0
+typedef void * dwar_extractor_handle_t;
+#endif
+
 typedef enum AOTIntCond {
   INT_EQZ = 0,
   INT_EQ,
@@ -251,6 +255,9 @@ typedef struct AOTCompData {
   uint32 aux_stack_size;
 
   WASMModule *wasm_module;
+#if WASM_ENABLE_DEBUG_AOT != 0
+  dwar_extractor_handle_t extractor;
+#endif
 } AOTCompData;
 
 typedef struct AOTNativeSymbol {