windows: stacktrace fix line info printing

Author: star-tek-mb

lib/std/debug.zig

@@ -1134,7 +1134,16 @@ fn readMachODebugInfo(allocator: mem.Allocator, macho_file: File) !ModuleDebugIn
 fn printLineFromFileAnyOs(out_stream: anytype, line_info: LineInfo) !void {
     // Need this to always block even in async I/O mode, because this could potentially
     // be called from e.g. the event loop code crashing.
-    var f = try fs.cwd().openFile(line_info.file_name, .{ .intended_io_mode = .blocking });
+    var path = line_info.file_name;
+
+    if (native_os == .windows) {
+        var buffer: [std.fs.MAX_PATH_BYTES*2]u8 = undefined;
+        var fba = std.heap.FixedBufferAllocator.init(&buffer);
+        var resolved_path = try std.fs.path.resolve(fba.allocator(), &.{path});
+        path = try std.fmt.allocPrint(fba.allocator(), "\\??\\{s}{s}", .{if (resolved_path[0] == '\\') "UNC" else "", resolved_path});
+    }
+
+    var f = try fs.cwd().openFile(path, .{ .intended_io_mode = .blocking });
     defer f.close();
     // TODO fstat and make sure that the file has the correct size