Delete root header file typedef.h.

Usage replaced with stdint.h, rtc_base/system/arch.h and
rtc_base/system/unused.h, as appropriate.

Bug: webrtc:6854
Change-Id: I97225465d14b969903d92979e2df3c3c05d35f18
Reviewed-on: https://webrtc-review.googlesource.com/90249
Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24100}
diff --git a/modules/audio_coding/codecs/ilbc/decode.c b/modules/audio_coding/codecs/ilbc/decode.c
index 7cba418..3848bc7 100644
--- a/modules/audio_coding/codecs/ilbc/decode.c
+++ b/modules/audio_coding/codecs/ilbc/decode.c
@@ -16,6 +16,9 @@
 
 ******************************************************************/
 
+// Defines WEBRTC_ARCH_BIG_ENDIAN, used below.
+#include "rtc_base/system/arch.h"
+
 #include "modules/audio_coding/codecs/ilbc/defines.h"
 #include "modules/audio_coding/codecs/ilbc/simple_lsf_dequant.h"
 #include "modules/audio_coding/codecs/ilbc/decoder_interpolate_lsf.h"