patch 8.0.0866: Solaris also doesn't have MIN and MAX

Problem:    Solaris also doesn't have MIN and MAX.
Solution:   Define MIN and MAX whenever they are not defined. (Ozaki Kiichi,
            closes #1939)
diff --git a/src/version.c b/src/version.c
index bbbdbe3..3595c1a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    866,
+/**/
     865,
 /**/
     864,