Warn on missing pkg-config, plus trivial comparator typo fix.

Change-Id: I68eef93ee70a934feb9a53cca050b81a4e66e26c
BUG: 921817
Signed-off-by: Justin Clift <jclift@redhat.com>
Reviewed-on: http://review.gluster.org/4672
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>
dht: fix a typo

Change-Id: Id6f156957e58aad06bf2602f880c7e4102b80fd1
BUG: 764890
Signed-off-by: JulesWang <w.jq0722@gmail.com>
Reviewed-on: http://review.gluster.org/4679
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
rpc: For AF_UNIX sockets, do not set keepalive option.

Change-Id: I65df52e89fe7783ff00c2b7a49be571d15e8f0d0
BUG: 920009
Signed-off-by: Venkatesh Somyajulu <vsomyaju@redhat.com>
Reviewed-on: http://review.gluster.org/4684
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>
iobuf: Added a function iobref_clear

Original-author: Venky Shankar <vshankar@redhat.com>

Change-Id: Ibf861db6c1b084b798d210962344487a1919aad2
BUG: 921942
Signed-off-by: Prashanth Pai <nullpai@gmail.com>
features/compress: Compression/DeCompression translator

Original-author : Venky Shankar <vshankar@redhat.com>

* When a writev call occurs, the client compresses the data before
  sending it to server. On the server, compressed data is decompressed.
  Similarly, when a readv call occurs, the server compresses the data
  before sending it to client. On the client, the compressed data is
  decompressed. Thus the amount of data sent over the wire is minimized.

* Compression/Decompression is done using Zlib library.

* During normal operation, this is the format of data sent over wire :
  <compressed-data> + trailer(8)
  The trailer contains the CRC32 checksum and length of original
  uncompressed data. This is used for validation.

* However in debug mode, gzip header is added and compressed data is
  dumped onto disk as a gzip file. This is to be used is testing only.

HOW TO USE
----------
Setting compression xlator options from CLI

Ex : gluster volume set <vol_name> compress on
     gluster volume set <vol_name> compress.buffer-size 32768
     gluster volume set <vol_name> compress.debug on

Change-Id: Ib7a66b6f1f70fe002b7c513588cdf75c69370805
BUG: 923540
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Prashanth Pai <nullpai@gmail.com>