Fix build errors when initializing wasm_val_t values with macros (#3007)

Errors were reported when initializing wasm_val_t values with WASM_I32_VAL like macros.
```
 error: missing initializer for member ‘wasm_val_t::__paddings’ [-Werror=missing-field-initializers]
   64 |     wasm_val_t res = {WASM_INIT_VAL};
```
And rename DEPRECATED to WASM_API_DEPRECATED to avoid using defines with generic names.

core/iwasm/include/wasm_c_api.h

@@ -22,12 +22,12 @@
 #endif
 
 #if defined(__GNUC__) || defined(__clang__)
-#define DEPRECATED __attribute__((deprecated))
+#define WASM_API_DEPRECATED __attribute__((deprecated))
 #elif defined(_MSC_VER)
-#define DEPRECATED __declspec(deprecated)
+#define WASM_API_DEPRECATED __declspec(deprecated)
 #else
 #pragma message("WARNING: You need to implement DEPRECATED for this compiler")
-#define DEPRECATED
+#define WASM_API_DEPRECATED
 #endif
 
 #ifdef __cplusplus
@@ -231,7 +231,7 @@ WASM_DECLARE_OWN(engine)
  */
 WASM_API_EXTERN own wasm_engine_t* wasm_engine_new(void);
 WASM_API_EXTERN own wasm_engine_t* wasm_engine_new_with_config(wasm_config_t*);
-DEPRECATED WASM_API_EXTERN own wasm_engine_t *
+WASM_API_DEPRECATED WASM_API_EXTERN own wasm_engine_t *
 wasm_engine_new_with_args(mem_alloc_type_t type, const MemAllocOption *opts);
 
 // Store
@@ -828,12 +828,12 @@ static inline void* wasm_val_ptr(const wasm_val_t* val) {
 #endif
 }
 
-#define WASM_I32_VAL(i) {.kind = WASM_I32, .of = {.i32 = i}}
-#define WASM_I64_VAL(i) {.kind = WASM_I64, .of = {.i64 = i}}
-#define WASM_F32_VAL(z) {.kind = WASM_F32, .of = {.f32 = z}}
-#define WASM_F64_VAL(z) {.kind = WASM_F64, .of = {.f64 = z}}
-#define WASM_REF_VAL(r) {.kind = WASM_ANYREF, .of = {.ref = r}}
-#define WASM_INIT_VAL {.kind = WASM_ANYREF, .of = {.ref = NULL}}
+#define WASM_I32_VAL(i) {.kind = WASM_I32, .__paddings = {0}, .of = {.i32 = i}}
+#define WASM_I64_VAL(i) {.kind = WASM_I64, .__paddings = {0}, .of = {.i64 = i}}
+#define WASM_F32_VAL(z) {.kind = WASM_F32, .__paddings = {0}, .of = {.f32 = z}}
+#define WASM_F64_VAL(z) {.kind = WASM_F64, .__paddings = {0}, .of = {.f64 = z}}
+#define WASM_REF_VAL(r) {.kind = WASM_ANYREF, .__paddings = {0}, .of = {.ref = r}}
+#define WASM_INIT_VAL {.kind = WASM_ANYREF, .__paddings = {0}, .of = {.ref = NULL}}
 
 #define KILOBYTE(n) ((n) * 1024)