introduced some caching to avoid pointless recursion

https://its.cern.ch/jira/browse/LBCORE-495

* dev/cmake:
  allow overrides of LCG_externals_*.txt
  allow absolute paths in LCG_externals_*.txt files
  removed duplicated test
  fixed dependency of the <dictionary>PCM target
  fixed pcm support in CMake builds

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7505 53ecefc3-a64d-0410-9bdf-b8581fa3287e

All the LCG_externals_*.txt in the CMAKE_PREFIX_PATH (+ CMTPROJECTPATH, with
optional suffix dir LCG_<version>) are taken into account to fill the
CMAKE_PREFIX_PATH for the externals.

The first LCG_Externals_*.txt in the path overrides the content of the
following ones, and the last one is used to determine the base location of
the externals.

The custom command used for the <dictionary>PCM  target must depend on
<dictionary>Gen (and not on the pcm file) to avoid that the genreflex
command is called multiple times.

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7503 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7502 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7501 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7500 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7499 53ecefc3-a64d-0410-9bdf-b8581fa3287e

Merge branch 'JIRA/GAUDI-974'

* JIRA/GAUDI-974:
  Fixed logic of OutputStream::decodeAlgorithms.
  updated reference file after the changes in OutputStream
  wrap debug messages in "if(DEBUG)" conditions
  minor aestethic change in the debug messages
  fixed segfault when only AlgDependentItemList is defined
  allow nested test suites in GAUDI_QMTEST_DEFAULT_SUITE
  temporary: test for the conditional output in OutputStream (GAUDI-974)
  GAUDI-974: modified OutputStream to allow algorithm dependent outputs

Conflicts:
	GaudiPolicy/doc/release.notes

https://its.cern.ch/jira/browse/GAUDI-974

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7498 53ecefc3-a64d-0410-9bdf-b8581fa3287e

* dev/cmake:
  removed some dead code in ConfigurableDb.py
  modified UseHEPTools to pick up the system compiler on Ubuntu
  fixed dependency problem between generated headers and genreflex step

Conflicts:
	GaudiKernel/doc/release.notes

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7497 53ecefc3-a64d-0410-9bdf-b8581fa3287e

https://its.cern.ch/jira/browse/GAUDI-976

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7496 53ecefc3-a64d-0410-9bdf-b8581fa3287e

Modified genconf not to fail if the return type of a factory is not
known.
Added a test to verify the it works (CMake only).

https://its.cern.ch/jira/browse/GAUDI-975

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7495 53ecefc3-a64d-0410-9bdf-b8581fa3287e

Christopher Rob Jones authored Jul 01, 2014 and Marco Clemencic committed Jul 01, 2014

https://its.cern.ch/jira/browse/GAUDI-974

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7494 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7493 53ecefc3-a64d-0410-9bdf-b8581fa3287e

* dev/cmake:
  minor reorganization of ATLAS-specific settings
  modified createProjVersHeader.py to handle special cases
  consider athena_add_module to imply dependency on GaudiCoreSvc
  marked GENCONF_WITH_NO_INIT as advanced
  extended the other projects search path to cover ATLAS nightlies
  fixed GAUDI-966: hide confusing files in the build directory
  modified HEPToolsMacros to allow the use of CMakeTools (if it works)

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7492 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7491 53ecefc3-a64d-0410-9bdf-b8581fa3287e

From: Marco Clemencic <marco.clemencic@cern.ch>


git-svn-id: svn+ssh://svn.cern.ch/reps/gaudi/Gaudi/trunk@7490 53ecefc3-a64d-0410-9bdf-b8581fa3287e