Using fully qualified #include paths in ilbc code.

WebRTC internal code should always use include paths that start
from the root of the project and that clearly identify the header file.

This allows 'gn check' to actually keep dependencies under control
because 'gn check' cannot enforce anything if the include path
is not fully qualified (starting from the root of the project).

Bug: webrtc:8815
Change-Id: I36f01784fa5f5b77eefc02db479b1f7f6ee1a8c3
Reviewed-on: https://webrtc-review.googlesource.com/46263
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21871}
diff --git a/modules/audio_coding/codecs/ilbc/enhancer_interface.h b/modules/audio_coding/codecs/ilbc/enhancer_interface.h
index 17a0354..e305161 100644
--- a/modules/audio_coding/codecs/ilbc/enhancer_interface.h
+++ b/modules/audio_coding/codecs/ilbc/enhancer_interface.h
@@ -19,7 +19,7 @@
 #ifndef MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_ENHANCER_INTERFACE_H_
 #define MODULES_AUDIO_CODING_CODECS_ILBC_MAIN_SOURCE_ENHANCER_INTERFACE_H_
 
-#include "defines.h"
+#include "modules/audio_coding/codecs/ilbc/defines.h"
 
 /*----------------------------------------------------------------*
  * interface for enhancer