Fix x86-32 compile warning and update document (#1164)

Author: wenyongh

core/iwasm/compilation/aot_emit_aot_file.c

@@ -2103,8 +2103,10 @@ aot_resolve_target_info(AOTCompContext *comp_ctx, AOTObjectData *obj_data)
         return false;
     }
 
-    strncpy(obj_data->target_info.arch, comp_ctx->target_arch,
-            sizeof(obj_data->target_info.arch) - 1);
+    bh_assert(sizeof(obj_data->target_info.arch)
+              == sizeof(comp_ctx->target_arch));
+    bh_memcpy_s(obj_data->target_info.arch, sizeof(obj_data->target_info.arch),
+                comp_ctx->target_arch, sizeof(comp_ctx->target_arch));
 
     return true;
 }

doc/wamr_api.md

@@ -107,7 +107,7 @@ Below is the reference implementation of the pub application. It utilizes a time
 
 ``` C
 /* Timer callback */
-void timer_update(user_timer_t timer
+void timer_update(user_timer_t timer)
 {
     attr_container_t *event;