Improved -Wdeprecated-declarations warning suppression

Don't depend on OS X SDK version anymore, since my 10.6 dashboard machine also has this warning;
instead always suppress the warning on OS X.  If gcc is new enough, suppress only within
the header, otherwise we're forced to suppress for the remainer of the translation unit.

Change-Id: Ibfa92d5895cb59c20dbc2c894e56c9e875e6fc9a
Merge topic 'improved-deprecation-suppression' into master

d094173f Improved -Wdeprecated-declarations warning suppression
Removed obsolete checks for compiler 'bool' support

As VTK 6 has dropped support for antique compilers, surely we can assume 'bool' exists in 2013.
Removed VTK_COMPILER_HAS_BOOL checks.  Kept vtkstd_bool with VTK_LEGACY_REMOVE.

Change-Id: I5ae1143eb78470307cf2a5ba5ff8fa77403d4b4d
Merge topic 'purge-obsolete-bool-checks' into master

6bc6866a Removed obsolete checks for compiler 'bool' support
COMP: fixed compilation error using llvm's libc++

ifstream's read() method returns a reference, which
can never be NULL yet vtkEnSightGoldBinaryReader was
comparing the result against NULL.  This fails to
compile if using llvm's libc++.  So, instead of
"if (read() == NULL)" it now does "if (!read())"
which does the right thing (I think)
since operator! is overloaded.

Change-Id: I5412da06795982826bb0df5c7dd82e53b1754e5d
Merge topic 'libc++-fixes' into master

cc1e92f9 COMP: fixed compilation error using llvm's libc++