diff --git a/src/file.h b/src/file.h
index aeea2a186..c74eb1585 100644
--- a/src/file.h
+++ b/src/file.h
@@ -1,5 +1,5 @@
-#ifndef _FILE_H_
-#define _FILE_H_
+#ifndef _FILELS_H_ // This was just _FILE_H_, but that interfered with Cygwin
+#define _FILELS_H_
 
 struct file_data {
     int size;
@@ -9,4 +9,4 @@ struct file_data {
 extern struct file_data *file_load(char *filename);
 extern void file_free(struct file_data *filedata);
 
-#endif
\ No newline at end of file
+#endif