Remove AndroidConfig.h.

This change leaves soong references.

Change-Id: Iee32b6b97ad9711f69e999c9d01f01d71562b63f
diff --git a/core/clang/config.mk b/core/clang/config.mk
index e747362..910c1a4 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -33,7 +33,8 @@
   -Werror=int-conversion
 
 # Disable overly aggressive warning for macros defined with a leading underscore
-# This happens in AndroidConfig.h, which is included nearly everywhere.
+# This used to happen in AndroidConfig.h, which was included everywhere.
+# TODO: can we remove this now?
 CLANG_CONFIG_EXTRA_CFLAGS += \
   -Wno-reserved-id-macro