patch 9.0.1927: patch 1916 (fixed terminal size) not optimal

Problem:  patch 1916 (fixed terminal size) not optimal
Solution: Add defines to make it easier changeable later

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/libvterm/include/vterm.h b/src/libvterm/include/vterm.h
index a3aa17a..48deebe 100644
--- a/src/libvterm/include/vterm.h
+++ b/src/libvterm/include/vterm.h
@@ -21,6 +21,10 @@
 typedef unsigned short		uint16_t;
 typedef unsigned int		uint32_t;
 
+// VIM: define max screen cols and rows
+#define VTERM_MAX_COLS 1000
+#define VTERM_MAX_ROWS 1000
+
 #define VTERM_VERSION_MAJOR 0
 #define VTERM_VERSION_MINOR 3
 #define VTERM_VERSION_PATCH 3
diff --git a/src/libvterm/src/screen.c b/src/libvterm/src/screen.c
index 7b3322b..fd76777 100644
--- a/src/libvterm/src/screen.c
+++ b/src/libvterm/src/screen.c
@@ -776,14 +776,14 @@
     if(screen->sb_buffer)
       vterm_allocator_free(screen->vt, screen->sb_buffer);
 
-    if (new_cols > 1000)
-      new_cols = 1000;
+    if (new_cols > VTERM_MAX_COLS)
+      new_cols = VTERM_MAX_COLS;
 
     screen->sb_buffer = vterm_allocator_malloc(screen->vt, sizeof(VTermScreenCell) * new_cols);
   }
 
-  if (new_rows > 1000)
-    new_rows = 1000;
+  if (new_rows > VTERM_MAX_ROWS)
+    new_rows = VTERM_MAX_ROWS;
 
   resize_buffer(screen, 0, new_rows, new_cols, !altscreen_active, fields);
   if(screen->buffers[BUFIDX_ALTSCREEN])