patch 9.0.0172: trying to allocate zero bytes

Problem:    Trying to allocate zero bytes.
Solution:   Do not allocate the proptype array when there are none.
            (closes #10867)
diff --git a/src/version.c b/src/version.c
index 63a0eae..dec5fbd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    172,
+/**/
     171,
 /**/
     170,