Refactor `button & ~MOD_MASK' as `STRIP_BUTTON_MODIFIERS(button)'.

This refactors all instances of bitwise-ANDs with `~MOD_MASK'. There is
a handful of more complex instances I left unchanged (in cube.c, midend.c,
and twiddle.c), since those AND with `~MOD_MASK | MOD_NUM_KEYPAD' or
similar. I don't think it's worth writing a macro for those cases.

Also document this new macro's usage in devel.but.

1 files changed, 1 insertions, 1 deletions

diff --git a/towers.c b/towers.c
index c26e530..4dd9484 100644
--- a/towers.c
+++ b/towers.c
@@ -1424,7 +1424,7 @@ static char *interpret_move(const game_state *state, game_ui *ui,
     int tx, ty;
     char buf[80];
 
-    button &= ~MOD_MASK;
+    button = STRIP_BUTTON_MODIFIERS(button);
 
     tx = FROMCOORD(x);
     ty = FROMCOORD(y);