patch 8.1.1125: libvterm does not handle the window position report
Problem: Libvterm does not handle the window position report.
Solution: Let libvterm call the fallback CSI handler when not handling CSI
sequence. Handle the window position report in Vim.
diff --git a/src/proto/ui.pro b/src/proto/ui.pro
index 774a308..26cfd47 100644
--- a/src/proto/ui.pro
+++ b/src/proto/ui.pro
@@ -11,6 +11,7 @@
int ui_get_shellsize(void);
void ui_set_shellsize(int mustset);
void ui_new_shellsize(void);
+int ui_get_winpos(int *x, int *y, varnumber_T timeout);
void ui_breakcheck(void);
void ui_breakcheck_force(int force);
void clip_init(int can_use);