Merge pull request #4341 from mysterywolf/unlink

[libc][iar][gcc] 优化remove函数

components/libc/compilers/dlib/syscall_remove.c

@@ -9,16 +9,16 @@
  */
 #include <rtthread.h>
 #ifdef RT_USING_DFS
-#include <dfs_file.h>
+#include <dfs_posix.h>
 #endif
 #include <yfuns.h>
 
 #pragma module_name = "?remove"
 int remove(const char *val)
 {
-#ifdef RT_USING_DFS
-    dfs_file_unlink(val);
+#ifndef RT_USING_DFS
+    return -1;
+#else
+    return unlink(val);
 #endif
-
-    return 0;
 }

components/libc/compilers/newlib/syscalls.c

@@ -197,12 +197,9 @@ int
 _unlink_r(struct _reent *ptr, const char *file)
 {
 #ifndef RT_USING_DFS
-    return 0;
+    return -1;
 #else
-    int rc;
-
-    rc = unlink(file);
-    return rc;
+    return unlink(file);
 #endif
 }