diff -u -r ../coreutils-8.27/src/tac.c ./src/tac.c
--- ../coreutils-8.27/src/tac.c	2017-02-18 04:18:29.000000000 +0100
+++ ./src/tac.c	2017-07-02 23:32:45.765137258 +0200
@@ -67,7 +67,7 @@
 
 
 #ifndef DEFAULT_TMPDIR
-# define DEFAULT_TMPDIR "/tmp"
+# define DEFAULT_TMPDIR "@TERMUX_PREFIX@/tmp"
 #endif
 
 /* The number of bytes per atomic read. */