Revert "Don't define |r_debug| and |link_map| on Android releases 21 and later"

src/common/android/include/link.h

Index: src/common/android/include/link.h
diff --git a/src/common/android/include/link.h b/src/common/android/include/link.h
index 58180a8ec365ba65cfd58406ab63942bc2090aaf..e7ff8e2d8702b0037921b50c99b94f02758f6e2a 100644
--- a/src/common/android/include/link.h
+++ b/src/common/android/include/link.h
@@ -30,18 +30,10 @@
 #ifndef GOOGLE_BREAKPAD_ANDROID_INCLUDE_LINK_H
 #define GOOGLE_BREAKPAD_ANDROID_INCLUDE_LINK_H
 
-// Android doesn't provide all the data-structures required in
-// its <link.h> before release 21. Provide custom version here and
-// rename Bionic-provided structures to avoid conflicts.
-
-#define r_debug   __bionic_r_debug
-#define link_map  __bionic_link_map
-
+/* Android doesn't provide all the data-structures required in its <link.h>.
+   Provide custom version here. */
 #include_next <link.h>
 
-#undef r_debug
-#undef link_map
-
 // TODO(rmcilroy): Remove this file once the ndk is updated for other
 // architectures - crbug.com/358831
 #if !defined(__aarch64__) && !defined(__x86_64__) && \