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