Discard MSC_SCAN events

Given that only EV_KEY events are being mapped, without their scancode
counterparts, we just drop all scancode events to avoid having to map
them too, to syncing it with the corresponding mapped keys. This is
expected to be harmless.

README.md

@@ -56,6 +56,12 @@ I'm maintaining an Archlinux package on AUR:
 
 - <https://aur.archlinux.org/packages/interception-caps2esc>
 
+I don't use Ubuntu and recommend Archlinux instead, as it provides the AUR, so I
+don't maintain PPAs. For more information on Ubuntu/Debian installation check
+this:
+
+- <https://askubuntu.com/questions/979359/how-do-i-install-caps2esc>
+
 ## Caveats
 
 As always, there's always a caveat:

caps2esc.c

@@ -39,6 +39,9 @@ int main(void) {
     setbuf(stdin, NULL), setbuf(stdout, NULL);
 
     while (read_event(&input)) {
+        if (input.type == EV_MSC && input.code == MSC_SCAN)
+            continue;
+
         if (input.type != EV_KEY) {
             write_event(&input);
             continue;
@@ -66,6 +69,8 @@ int main(void) {
             if (!esc_give_up && input.value) {
                 esc_give_up = 1;
                 write_event(&ctrl_down);
+                write_event(&syn);
+                usleep(20000);
             }
         } else if (equal(&input, &capslock_down)) {
             capslock_is_down = 1;