xrootd: add XrdClient/XrdClientSid.hh private header to incl. path

Another xrootd private header XrdClient/XrdClientSid.hh is being used
by CMSSW and no more distributed. Adding it to ./include/xrootd/private.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #150 from davidlt/xrootd-add-xrddlientsid-hh

[CMSSW_7_0_X] xrootd add XrdClient/XrdClientSid.hh private header
Merge remote-tracking branch 'origin/IB/CMSSW_7_0_X/stable' into IB/CMSSW_7_0_X/devel-gcc472
Merge remote-tracking branch 'origin/IB/CMSSW_7_0_X/devel-gcc472' into IB/CMSSW_7_0_X/devel-gcc48
xz: use *.gz for source instead of *.xz

On Darwin platform there is no xz-utils package provided by Apple thus
we cannot expand LZMA2 archives. Use gzip or bz2 for sources.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
xdaq-toolfile: XDAQ OS must be macosx, not darwin

Change XDAQ OS to be 'macosx' instead of 'darwin'. Headers are installed
under 'macosx' directory and SCRAM complains if directory is missing.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
xerces-c: fix compilation on Darwin platform

Remove Darwin 32-bit support lines and fix typos in 64-bit support. By
default Darwin is 64-bit.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>