Fix utf-8 char path in windows

The file 'E:\安安\scrcpy-win64-v1.12.1-1-g31bd950\scrcpy-server'
exists, however, it will show msg as follow:

    INFO: scrcpy 1.12.1 <https://github.com/Genymobile/scrcpy>
    stat: No such file or directory
    ERROR: 'E:\安安\scrcpy-win64-v1.12.1-1-g31bd950\scrcpy-server' does
    not exist or is not a regular file
    Press any key to continue...

This patch fixes it.

Signed-off-by: Yu-Chen Lin <npes87184@gmail.com>
Signed-off-by: Romain Vimont <rom@rom1v.com>

app/src/command.c

@@ -4,9 +4,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 
 #include "config.h"
 #include "common.h"
@@ -205,14 +202,3 @@ process_check_success(process_t proc, const char *name) {
     }
     return true;
 }
-
-bool
-is_regular_file(const char *path) {
-    struct stat path_stat;
-    int r = stat(path, &path_stat);
-    if (r) {
-        perror("stat");
-        return false;
-    }
-    return S_ISREG(path_stat.st_mode);
-}