patch 8.1.1520: popup windows are ignored when dealing with mouse position

Problem:    Popup windows are ignored when dealing with mouse position
Solution:   Find the mouse position inside a popup window.  Allow for modeless
            selection.
diff --git a/src/proto/popupwin.pro b/src/proto/popupwin.pro
index 2a377a7..a274446 100644
--- a/src/proto/popupwin.pro
+++ b/src/proto/popupwin.pro
@@ -1,4 +1,6 @@
 /* popupwin.c */
+int popup_height(win_T *wp);
+int popup_width(win_T *wp);
 void popup_adjust_position(win_T *wp);
 void f_popup_clear(typval_T *argvars, typval_T *rettv);
 void f_popup_create(typval_T *argvars, typval_T *rettv);
diff --git a/src/proto/ui.pro b/src/proto/ui.pro
index 26cfd47..e920029 100644
--- a/src/proto/ui.pro
+++ b/src/proto/ui.pro
@@ -65,7 +65,7 @@
 void yank_cut_buffer0(Display *dpy, VimClipboard *cbd);
 int jump_to_mouse(int flags, int *inclusive, int which_button);
 int mouse_comp_pos(win_T *win, int *rowp, int *colp, linenr_T *lnump);
-win_T *mouse_find_win(int *rowp, int *colp);
+win_T *mouse_find_win(int *rowp, int *colp, mouse_find_T popup);
 int get_fpos_of_mouse(pos_T *mpos);
 int vcol2col(win_T *wp, linenr_T lnum, int vcol);
 void ui_focus_change(int in_focus);