revent: added gamepad recording + major refactor

- Added support for gamepad recording. This type of recording contains
  only the events from a gamepad device (which is automatically
  identified). The details of this devices are collected and stored as
  part of the recording. On playback, uinput is used to create a virtual
  gamepad and replay into it.
- A "mode" field has been added to the recording format to help
  distinguish between the normal and gamepad recording types.
- A field for the total number of input events has been added before the
  start of the event stream (after the device description).
- The structure of revent code has undergone a major overhaul to improve
  maintainability and robustness.
- More detailed "info" command output.
- Updated Makefile to support debug/production builds.

wlauto/external/revent/Makefile

@@ -1,7 +1,12 @@
 # CROSS_COMPILE=aarch64-linux-gnu- make
 #
 CC=gcc
-CFLAGS=-static -lc
+
+ifdef DEBUG
+	CFLAGS=-static -lc -g
+else
+	CFLAGS=-static -lc -O2
+endif
 
 revent: revent.c
 	$(CROSS_COMPILE)$(CC) $(CFLAGS) revent.c -o revent