This provides a new struct that contains a buffer for the RPC
message header+payload, as well as a decoded copy of the message
header. There is an API for applying a XDR encoding & decoding
of the message headers and payloads. There are also APIs for
maintaining a simple FIFO queue of message instances.

Expected usage scenarios are:

To send a message

   msg = virNetMessageNew()

   ...fill in msg->header fields..
   virNetMessageEncodeHeader(msg)
   ...loook at msg->header fields to determine payload filter
   virNetMessageEncodePayload(msg, xdrfilter, data)
   ...send msg->bufferLength worth of data from buffer

To receive a message

   msg = virNetMessageNew()
   ...read VIR_NET_MESSAGE_LEN_MAX of data into buffer
   virNetMessageDecodeLength(msg)
   ...read msg->bufferLength-msg->bufferOffset of data into buffer
   virNetMessageDecodeHeader(msg)
   ...look at msg->header fields to determine payload filter
   virNetMessageDecodePayload(msg, xdrfilter, data)
   ...run payload processor

* src/Makefile.am: Add to libvirt-net-rpc.la
* src/rpc/virnetmessage.c, src/rpc/virnetmessage.h: Internal
  message handling API.
* testutils.c, testutils.h: Helper for printing binary differences
* virnetmessagetest.c: Validate all XDR encoding/decoding

Make virtTestLoadFile allocate the buffer to read the file into.

Fix logic error in virtTestLoadFile, stop reading on the first empty line.

Use virFileReadLimFD in virtTestCaptureProgramOutput to avoid manual
buffer handling.

A few of the tests were missing basic sanity checks, while most
of them were doing copy-and-paste initialization (in fact, some
of them pasted the argc > 1 check more than once!).  It's much
nicer to do things in one common place, and minimizes the size of
the next patch that fixes getcwd usage.

* tests/testutils.h (EXIT_AM_HARDFAIL): New define.
(progname, abs_srcdir): Define for all tests.
(VIRT_TEST_MAIN): Change callback signature.
* tests/testutils.c (virtTestMain): Do more common init.
* tests/commandtest.c (mymain): Simplify.
* tests/cputest.c (mymain): Likewise.
* tests/esxutilstest.c (mymain): Likewise.
* tests/eventtest.c (mymain): Likewise.
* tests/hashtest.c (mymain): Likewise.
* tests/networkxml2xmltest.c (mymain): Likewise.
* tests/nodedevxml2xmltest.c (myname): Likewise.
* tests/nodeinfotest.c (mymain): Likewise.
* tests/nwfilterxml2xmltest.c (mymain): Likewise.
* tests/qemuargv2xmltest.c (mymain): Likewise.
* tests/qemuhelptest.c (mymain): Likewise.
* tests/qemuxml2argvtest.c (mymain): Likewise.
* tests/qemuxml2xmltest.c (mymain): Likewise.
* tests/qparamtest.c (mymain): Likewise.
* tests/sexpr2xmltest.c (mymain): Likewise.
* tests/sockettest.c (mymain): Likewise.
* tests/statstest.c (mymain): Likewise.
* tests/storagepoolxml2xmltest.c (mymain): Likewise.
* tests/storagevolxml2xmltest.c (mymain): Likewise.
* tests/virbuftest.c (mymain): Likewise.
* tests/virshtest.c (mymain): Likewise.
* tests/vmx2xmltest.c (mymain): Likewise.
* tests/xencapstest.c (mymain): Likewise.
* tests/xmconfigtest.c (mymain): Likewise.
* tests/xml2sexprtest.c (mymain): Likewise.
* tests/xml2vmxtest.c (mymain): Likewise.

Before this patch, the testsuite was noisy:

TEST: qemuargv2xmltest
      ........................................ 40
      ................20:41:28.046: warning : qemuParseCommandLine:6565 : unknown QEMU argument '-unknown', adding to the qemu namespace
20:41:28.046: warning : qemuParseCommandLine:6565 : unknown QEMU argument 'parameter', adding to the qemu namespace
.                        57  OK
PASS: qemuargv2xmltest

It's not a real failure (which is why the test was completing
successfully), so much as an intentional warning to the user that use
of the qemu namespace has the potential for undefined effects that
leaked through the default logging behavior.  After this patch series,
all tests can access any logged data, and this particular test can
explicitly check for the presence or absence of the warning, such that
the test output becomes:

TEST: qemuargv2xmltest
      ........................................ 40
      .................                        57  OK
PASS: qemuargv2xmltest

* tests/testutils.h (virtTestLogContentAndReset): New prototype.
* tests/testutils.c (struct virtTestLogData): New struct.
(virtTestLogOutput, virtTestLogClose, virtTestLogContentAndReset):
New functions.
(virtTestMain): Always capture log data emitted during tests.
* tests/qemuargv2xmltest.c (testCompareXMLToArgvHelper, mymain):
Use flag to mark which tests expect noisy stderr.
(testCompareXMLToArgvFiles): Add parameter to test whether stderr
was appropriately silent.

* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done

Only print out '.' for each test case, full test output can be
re-enabled with VIR_TEST_VERBOSE=1, or VIR_TEST_DEBUG=XXXX

Sample output now looks like

  TEST: statstest
        ........................................ 40
        ...................................      75  OK
  PASS: statstest
  TEST: qparamtest
        ................................         32  OK
  PASS: qparamtest
  TEST:
        ............                             12  OK

This appeases a new gnulib-provided "syntax-check".
* daemon/libvirtd.c (main): Use EXIT_FAILURE, not 1.
* proxy/libvirt_proxy.c (main): Likewise, and EXIT_SUCCESS, not 0.
* tests/conftest.c (main): Likewise.
* tests/reconnect.c (main): Likewise.
* tests/testutils.h (EXIT_AM_SKIP): Define.
* tests/nodeinfotest.c (mymain): Use EXIT_AM_SKIP, not 77.
* tests/qemuargv2xmltest.c: Likewise.
* tests/qemuxml2xmltest.c: Likewise.
* tests/virshtest.c (mymain): Likewise.

Provide a simple interface for other tests to lookup the testDebug variable.
Also remove a redundant error message in interface tests.

If anyone feels inclined to change this env variable to match the existing
LIBVIRT_* format, it should now be easier to do so.

* src/testutils.[ch]: make testDebug externally available

* src/testutilsqemu.c: if VIR_TEST_DEBUG is set, dump the qemu
  driver capabilities to stderr

* po/id.po: Likewise.
* qemud/remote_generate_stubs.pl: Likewise.
* src/virsh.c: Likewise.
* tests/testutils.c: Likewise.
* tests/testutils.h: Likewise.
* RENAMES: Likewise.

Done with these commands:
git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* vim:(.|\n)*,\n,'

git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* Local variables:\n(.|\n)*,\n,'

* Makefile.cfg (local-checks-to-skip): Remove sc_trailing_blank.
* .x-sc_trailing_blank: New file, to exempt the few binary files.