patch 8.0.1737: fchown() used when it is not supported

Problem:    fchown() used when it is not supported.
Solution:   Add #ifdef.
diff --git a/src/version.c b/src/version.c
index aff6c6d..a7720a7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1737,
+/**/
     1736,
 /**/
     1735,