emacs-27 ee6c702: Fix error with fn key in NS port (bug#44533)

[Alan Third]

branch: emacs-27
commit ee6c702e1895d88ee7e6f57bc6778694239ead76
Author: Alan Third <alan@idiocy.org>
Commit: Alan Third <alan@idiocy.org>

    Fix error with fn key in NS port (bug#44533)
    
    * src/nsterm.m ([EmacsView keyDown:]): Move the correction for fn key
    handling to before the modifiers are calculated.
    
    (cherry picked from commit 7970610d48701a949ce443c94c71eac47d044197)
---
 src/nsterm.m | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/src/nsterm.m b/src/nsterm.m
index 4defeee..af06968 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -6350,6 +6350,14 @@ not_in_argv (NSString *arg)
             code = 0xFF08; /* backspace */
           else
             code = fnKeysym;
+
+          /* Function keys (such as the F-keys, arrow keys, etc.) set
+             modifiers as though the fn key has been pressed when it
+             hasn't.  Also some combinations of fn and a function key
+             return a different key than was pressed (e.g. fn-<left>
+             gives <home>).  We need to unset the fn key flag in these
+             cases.  */
+          flags &= ~NS_FUNCTION_KEY_MASK;
         }
 
       /* The ⌘ and ⌥ modifiers can be either shift-like (for alternate
@@ -6371,17 +6379,6 @@ not_in_argv (NSString *arg)
       Lisp_Object kind = fnKeysym ? QCfunction : QCordinary;
       emacs_event->modifiers = EV_MODIFIERS2 (flags, kind);
 
-      /* Function keys (such as the F-keys, arrow keys, etc.) set
-         modifiers as though the fn key has been pressed when it
-         hasn't.  Also some combinations of fn and a function key
-         return a different key than was pressed (e.g. fn-<left> gives
-         <home>).  We need to unset the fn modifier in these cases.
-         FIXME: Can we avoid setting it in the first place?  */
-      if (fnKeysym && (flags & NS_FUNCTION_KEY_MASK))
-        emacs_event->modifiers
-          ^= parse_solitary_modifier (mod_of_kind (ns_function_modifier,
-                                                   QCfunction));
-
       if (NS_KEYLOG)
         fprintf (stderr, "keyDown: code =%x\tfnKey =%x\tflags = %x\tmods = 
%x\n",
                  code, fnKeysym, flags, emacs_event->modifiers);