mark to-do, add two types of page down

TODO.md

@@ -1,6 +1,6 @@
 # To do
 
-- [ ] Settle on a C standard (C11?), and use safer string handling functions provided by it.
+- [ ] Move to a later C standard (C11?) and use safer string handling functions provided by it.
   - The thing is, I kinda feel attached to C89-C99
 - [ ] Consider
   - See make lint for purported insecurities
@@ -18,6 +18,7 @@
 
 # Previously done
 
+- [x] Check that this compiles with the c99 standard
 - [x] Add minimalist version of rosenrot to its own branch
 - [x] Fix PageUp/PageDown shortcuts.
 - ~~[ ] Set [`webkit_web_context_set_sandbox_enabled`](<https://webkitgtk.org/reference/webkit2gtk/2.36.8/WebKitWebContext.html#webkit-web-context-set-sandbox-enabled>), as recommended [here](<https://blogs.gnome.org/mcatanzaro/2022/11/04/stop-using-qtwebkit/>)~~. Irrelevant with upgrade to libsoup3.

config.h

@@ -86,8 +86,10 @@ static struct {
     { CTRL,        KEY(equal),         zoomin             },
     { CTRL,        KEY(minus),         zoomout            },
     { CTRL,        KEY(0),             zoom_reset         },
-    { CTRL,        KEY(KP_Page_Up),    prev_tab           }, /* also try KEY(Page_Up) if this doesn't work on your machine */
-    { CTRL,        KEY(KP_Page_Down),  next_tab           }, /* ditto for KEY(Page_Down) */
+    { CTRL,        KEY(KP_Page_Up),    prev_tab           }, 
+    { CTRL,        KEY(KP_Page_Down),  next_tab           }, 
+    { CTRL,        KEY(Page_Up),       prev_tab           }, // working hypothesis: Page_UP vs KP_Page_Up might depend on whether the user has a numpad
+    { CTRL,        KEY(Page_Down),     next_tab           }, 
     { CTRL,        KEY(t),             new_tab            },
     { CTRL,        KEY(w),             close_tab          },
     { 0x0,         KEY(F11),           toggle_fullscreen  },