diff -ruwN source/src/fccache.c source-new/src/fccache.c
--- source/src/fccache.c	2019-06-10 05:36:37.000000000 -0600
+++ source-new/src/fccache.c	2019-07-16 17:13:18.730013599 -0600
@@ -1526,7 +1526,7 @@
 #if defined(_WIN32)
 	    if (_locking (fd, _LK_LOCK, 1) == -1)
 		goto bail;
-#else
+#elif !defined(__redox__)
 	    struct flock fl;
 
 	    fl.l_type = F_WRLCK;
@@ -1556,7 +1556,7 @@
     {
 #if defined(_WIN32)
 	_locking (fd, _LK_UNLCK, 1);
-#else
+#elif !defined(__redox__)
 	struct flock fl;
 
 	fl.l_type = F_UNLCK;