使得DragonOS kernel 能为riscv64编译通过(尚未能启动) (#457)

* 使得DragonOS kernel 能为riscv64编译通过(尚未能启动)

* 修正了系统调用号声明不正确的问题，同时添加了编译配置文档

.vscode/settings.json

@@ -171,7 +171,8 @@
         "mman.h": "c",
         "clocksource.h": "c",
         "ata.h": "c",
-        "barrier": "c"
+        "barrier": "c",
+        "charconv": "c"
     },
     "C_Cpp.errorSquiggles": "enabled",
     "esbonio.sphinx.confDir": "",
@@ -180,8 +181,12 @@
         "./kernel/Cargo.toml",
         "./tools/Cargo.toml",
     ],
+    // "rust-analyzer.cargo.target": "riscv64imac-unknown-none-elf",
+    "rust-analyzer.cargo.target": "x86_64-unknown-none",
     "rust-analyzer.check.overrideCommand": [
         "make",
-        "check"
+        "check",
+        
     ],
+    
 }