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)

src/terminal.c

@@ -92,9 +92,11 @@
 
 #if defined(FEAT_TERMINAL) || defined(PROTO)
 
-#ifdef WIN3264
-# define MIN(x,y) (x < y ? x : y)
-# define MAX(x,y) (x > y ? x : y)
+#ifndef MIN
+# define MIN(x,y) ((x) < (y) ? (x) : (y))
+#endif
+#ifndef MAX
+# define MAX(x,y) ((x) > (y) ? (x) : (y))
 #endif
 
 #include "libvterm/include/vterm.h"

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    866,
 /**/
     865,
 /**/