android 4.2.2_r1 SDK的一個錯誤

最近同步了android 4.2.2_r1版的源碼，想編譯sdk。
編譯了幾個小時後，忽然出現關於javadoc的錯誤：
Docs droiddoc: out/target/common/docs/doc-comment-check
DroidDoc took 215 sec. to write docs to out/target/common/docs/doc-comment-check
Docs droiddoc: out/target/common/docs/online-sdk
DroidDoc took 170 sec. to write docs to out/target/common/docs/online-sdk
Docs droiddoc: out/target/common/docs/ds
DroidDoc took 147 sec. to write docs to out/target/common/docs/ds
Docs droiddoc: out/target/common/docs/online-gcm-ref
javadoc: error - No packages or classes specified.
usage: javadoc [options] [packagenames] [sourcefiles] [@files]
-overview <file>          Read overview documentation from HTML file
-public                   Show only public classes and members
-protected                Show protected/public classes and members (default)
-package                  Show package/protected/public classes and members
-private                  Show all classes and members
-help                     Display command line options and exit
-doclet <class>           Generate output via alternate doclet
-docletpath <path>        Specify where to find doclet class files
-sourcepath <pathlist>    Specify where to find source files
-classpath <pathlist>     Specify where to find user class files
-exclude <pkglist>        Specify a list of packages to exclude
-subpackages <subpkglist> Specify subpackages to recursively load
-breakiterator            Compute 1st sentence with BreakIterator
-bootclasspath <pathlist> Override location of class files loaded
  by the bootstrap class loader
-source <release>         Provide source compatibility with specified release
-extdirs <dirlist>        Override location of installed extensions
-verbose                  Output messages about what Javadoc is doing
-locale <name>            Locale to be used, e.g. en_US or en_US_WIN
-encoding <name>          Source file encoding name
-quiet                    Do not display status messages
-J<flag>                  Pass <flag> directly to the runtime system

1 error
make: *** [out/target/common/docs/online-gcm-ref-timestamp] Error 45

解決辦法：
在SOURCE_ROOT/frameworks/base目錄下，使用git revert 5f9922d7c3bce158e4c7a58929d4075e7c91e32e 命令同步到另外一個沒有錯的版本。

git revert 5f9922d7c3bce158e4c7a58929d4075e7c91e32e error: Your local changes to 'Android.mk' would be overwritten by merge.  Aborting. Please, commit your changes or stash them before you can merge. 解決辦法：重命名Android.mk，就不會出現overwrite的error了.