增加fstat系统调用号 (#6)

* 增加fstat系统调用号

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "rust-analyzer.linkedProjects": [
+        "./Cargo.toml",
+    ]
+}

src/platform/x86_64/nr.rs

@@ -45,3 +45,5 @@ pub const SYS_GETSOCKNAME: usize = 41;
 pub const SYS_GETPEERNAME: usize = 42;
 
 pub const SYS_GETTIMEOFDAY: usize = 43;
+
+pub const SYS_FSTAT: usize = 47;