refactor(options): remove `getoption_T` and introduce `OptVal` (#23850)

Removes the `getoption_T` struct and also introduces the `OptVal` struct
to unify the methods of getting/setting different option value types.
This is the first of many PRs to reduce code duplication in the Vim
option code as well as to make options easier to maintain. It also
increases the flexibility and extensibility of options. Which opens the
door for things like Array and Dictionary options.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index f1a3a679be..810f631a02 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1389,14 +1389,14 @@ void ex_diffthis(exarg_T *eap)
   diff_win_options(curwin, true);
 }
 
-static void set_diff_option(win_T *wp, int value)
+static void set_diff_option(win_T *wp, bool value)
 {
   win_T *old_curwin = curwin;
 
   curwin = wp;
   curbuf = curwin->w_buffer;
   curbuf->b_ro_locked++;
-  set_option_value_give_err("diff", (long)value, NULL, OPT_LOCAL);
+  set_option_value_give_err("diff", BOOLEAN_OPTVAL(value), OPT_LOCAL);
   curbuf->b_ro_locked--;
   curwin = old_curwin;
   curbuf = curwin->w_buffer;