some fixs and optimze

[jinzhongjia]

• fix: use std.fs.accessAbsolute to replace std.fs.openDirAbsolute
  This can solve the problem of file descriptors not being freed
• fix: verify zig version failed
  When the user has installed a higher zig, zvm verify zig version will failed, because the child process will use system environment variables
• optimize: simplify the logic of set_zig_version
• optimize: improve performance by using comptime
  rename origin detect func in architecture.zig to platform_str and make it become comptime func

[jinzhongjia]

And I delete this code

        std.posix.symlink(zig_path, symlink_path) catch |err| switch (err) {
            error.PathAlreadyExists => {
                try std.fs.cwd().deleteFile(symlink_path);
                try std.posix.symlink(zig_path, symlink_path);
            },
            else => return err,
        };

replace with this:

try std.posix.symlink(zig_path, symlink_path);

I think it's not necessary to retry the deletion in case of an error

[hendriknielaender]

And I delete this code

        std.posix.symlink(zig_path, symlink_path) catch |err| switch (err) {
            error.PathAlreadyExists => {
                try std.fs.cwd().deleteFile(symlink_path);
                try std.posix.symlink(zig_path, symlink_path);
            },
            else => return err,
        };

replace with this:

try std.posix.symlink(zig_path, symlink_path);

I think it's not necessary to retry the deletion in case of an error

error.PathAlreadyExists => {
                try std.fs.cwd().deleteFile(symlink_path);
                try std.posix.symlink(zig_path, symlink_path);
            },

IIRC I had a problem in the past, when there was already a symlink. So I'm not sure about this change.
11b3199

Let me try to reproduce it.

[hendriknielaender]

improve performance by using comptime

That's cool, we should use it wherever its possible 👍

[jinzhongjia]

Expectedly, the symlink should be removed in the above function

[hendriknielaender]

Expectedly, the symlink should be removed in the above function

True, overlooked it! 👍