make compilable on windows

src/main.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 const info = std.log.info;
 const debug = std.log.debug;
-const stderr = std.io.getStdErr().writer();
+//const stderr = std.io.getStdErr().writer();
 const print = std.debug.print;
 const eql = std.mem.eql;
 const Allocator = std.mem.Allocator;
@@ -297,9 +297,9 @@ fn read_config(allocator: Allocator, config_location: []const u8) !ArrayList(Otp
                     number_of_errors += 1;
                     switch (err) {
                         error.UnexpectedCharacter, error.InvalidFormat => {
-                            try stderr.print("Unexpected character in line {d} in file {s}. Line will be ignored.\n", .{ line_no, config_location });
+                            try std.io.getStdErr().writer().print("Unexpected character in line {d} in file {s}. Line will be ignored.\n", .{ line_no, config_location });
                             if (number_of_errors >= 10) {
-                                try stderr.print("too many parsing errors\n", .{});
+                                try std.io.getStdErr().writer().print("too many parsing errors\n", .{});
                                 return ArgumentError.TooManyParsinErrors;
                             }
                         },
@@ -322,13 +322,13 @@ fn read_config(allocator: Allocator, config_location: []const u8) !ArrayList(Otp
             error.BadPathName,
             error.InvalidWtf8,
             => {
-                try stderr.print("cannot open config file: {}\n", .{err});
+                try std.io.getStdErr().writer().print("cannot open config file: {}\n", .{err});
             },
             error.FileNotFound => {
-                try stderr.print("config file not found. Create a new config file in $HOME/.zig-totp or $XDG_CONFIG_HOME/zig-totp.\n", .{});
+                try std.io.getStdErr().writer().print("config file not found. Create a new config file in $HOME/.zig-totp or $XDG_CONFIG_HOME/zig-totp.\n", .{});
             },
             error.IsDir => {
-                try stderr.print("the configuration location must be a file, but is a directory.\n", .{});
+                try std.io.getStdErr().writer().print("the configuration location must be a file, but is a directory.\n", .{});
             },
             else => {
                 return err;