patch 8.2.1173: tee doesn't build on some systems

Problem:    Tee doesn't build on some systems.
Solution:   Include header files. (Dominique Pelle, closes #6431)
diff --git a/src/version.c b/src/version.c
index 7f71d14..2fa4704 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1173,
+/**/
     1172,
 /**/
     1171,