Several users had problems using 9.5-patch-01 on their MacOSX Lion (10.7.x) systems.  The G4 installation would complete successfully with no errors or warnings, but they could not build any applications (e.g., examples/novice/*).

The failure is due to G4SYSTEM being set to "Darwin-UNSUPPORTED", where the "UNSUPPORTED" tag itself is a consequence of the default Lion compiler being "clang" instead of "g++".

In cmake/Modules/Geant4LibraryBuildOptions.cmake, the compiler string for G4SYSTEM is determined by:

#------------------------------------------------------------------------------
# Determine the backward compatible compiler name
#
if(CMAKE_COMPILER_IS_GNUCXX)
    set(GEANT4_COMPILER "g++")
elseif(MSVC)
    set(GEANT4_COMPILER "VC")
elseif(CMAKE_CXX_COMPILER MATCHES "icpc.*")
    set(GEANT4_COMPILER "icc")
else()
    set(GEANT4_COMPILER "UNSUPPORTED")
endif()

Notice that in 9.5-patch-01 (and also in the trunk of SVN), the "clang" string is not a valid option.  

I see that in SVN, the "icc" option has been modified.  A further modification is needed, and ought to be tagged to include in 9.5-patch-02, to support "clang".

As a temporary workaround, since g++ is available on Lion, I have instructed users to set the "CMAKE_COMPILER_IS_GNUCXX=ON" option.