hdfs cleanup and compile test against CDH 4.4.

build_tools/build_detect_platform

@@ -289,7 +289,7 @@ if test "$USE_HDFS"; then
     exit 1
   fi
   HDFS_CCFLAGS="$HDFS_CCFLAGS -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -DUSE_HDFS"
-  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive hdfs/libhdfs.a -L$JAVA_HOME/jre/lib/amd64"
+  HDFS_LDFLAGS="$HDFS_LDFLAGS -Wl,--no-whole-archive -lhdfs -L$JAVA_HOME/jre/lib/amd64"
   HDFS_LDFLAGS="$HDFS_LDFLAGS -L$JAVA_HOME/jre/lib/amd64/server -L$GLIBC_RUNTIME_PATH/lib"
   HDFS_LDFLAGS="$HDFS_LDFLAGS -ldl -lverify -ljava -ljvm"
   COMMON_FLAGS="$COMMON_FLAGS $HDFS_CCFLAGS"

hdfs/README

@@ -1,19 +1,16 @@
 This directory contains the hdfs extensions needed to make rocksdb store
 files in HDFS.
 
-The hdfs.h file is copied from the Apache Hadoop 1.0 source code. 
-It defines the libhdfs library
-(http://hadoop.apache.org/common/docs/r0.20.2/libhdfs.html) to access 
-data in HDFS.  The libhdfs.a is copied from the Apache Hadoop 1.0 build. 
-It implements the API defined in hdfs.h. If your hadoop cluster is running
-a different hadoop release, then install these two files manually from your
-hadoop distribution and then recompile rocksdb.
+It has been compiled and testing against CDH 4.4 (2.0.0+1475-1.cdh4.4.0.p0.23~precise-cdh4.4.0).
+
+The configuration assumes that packages libhdfs0, libhdfs0-dev are 
+installed which basically means that hdfs.h is in /usr/include and libhdfs in /usr/lib
 
 The env_hdfs.h file defines the rocksdb objects that are needed to talk to an
 underlying filesystem. 
 
 If you want to compile rocksdb with hdfs support, please set the following
-enviroment variables appropriately:
+enviroment variables appropriately (also defined in setup.sh for convenience)
    USE_HDFS=1
    JAVA_HOME=/usr/local/jdk-6u22-64
    LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/jdk-6u22-64/jre/lib/amd64/server:/usr/local/jdk-6u22-64/jre/lib/amd64/:./snappy/libs

hdfs/env_hdfs.h

@@ -14,7 +14,7 @@
 #include "rocksdb/status.h"
 
 #ifdef USE_HDFS
-#include "hdfs/hdfs.h"
+#include <hdfs.h>
 
 namespace rocksdb {