patch 8.1.2265: when popup with "botleft" does not fit it flips incorrectly
Problem: When popup with "botleft" does not fit it flips incorrectly.
Solution: Only flip when there is more space on the other side. Add the
"posinvert" option to disable flipping and do it in both
directions if enabled. (closes #5151)
diff --git a/src/vim.h b/src/vim.h
index 97c1f6c..fe1e982 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -632,6 +632,7 @@
#define POPF_MAPPING 0x80 // mapping keys
#define POPF_INFO 0x100 // used for info of popup menu
#define POPF_INFO_MENU 0x200 // align info popup with popup menu
+#define POPF_POSINVERT 0x400 // vertical position can be inverted
#ifdef FEAT_TEXT_PROP
# define WIN_IS_POPUP(wp) ((wp)->w_popup_flags != 0)