Don't define __linux__ if it is already defined by the toolchain.
This change does not affect existing behavior at all and makes
the file compatible with new toolchain.

Change-Id: Ia33bb9372d1705ec538b414bf69773f093e4543c
diff --git a/include/arch/linux-arm/AndroidConfig.h b/include/arch/linux-arm/AndroidConfig.h
index f51ddb1..81f077f 100644
--- a/include/arch/linux-arm/AndroidConfig.h
+++ b/include/arch/linux-arm/AndroidConfig.h
@@ -199,7 +199,9 @@
 /*
  * Add any extra platform-specific defines here.
  */
+#ifndef __linux__
 #define __linux__
+#endif
 
 /*
  * Define if we have <malloc.h> header