Many platforms don't support backtraces. Fix compile for Solaris platform.

This change was tested with Solaris 10 on X86 and SPARC.

More information on Unix Backtrace Support
 - http://www.gnu.org/software/libc/manual/html_node/Backtraces.html

It is not supported on the following platforms:
 - https://www.gnu.org/software/gnulib/manual/html_node/execinfo_002eh.html

        Mac OS X 10.3,
        FreeBSD 6.0,
        NetBSD 5.0,
        OpenBSD 3.8,
        Minix 3.1.8,
        AIX 5.1,
        HP-UX 11,
        IRIX 6.5,
        OSF/1 5.1,
        Solaris 10,
        Cygwin,
        mingw,
        MSVC 9,
        Interix 3.5,
        BeOS.
Simplify defines.
Merge pull request #350 from lasergnu/stacktrace

Many platforms don't support backtraces. Fix compile for Solaris platform
Ticket #5952: Simplify redundant parentheses in pointer variable declarations.
Fixed #5931 (arrayIndexOutOfBoundsCond id reported instead of arrayIndexOutOfBounds)
Library: Handle FIlE_NOT_FOUND better
Fixed #5861 (valueFlowSubFunction: fp for float value)
Improve error message for Windows SEH adding more details if available
Merge pull request #351 from simartin/ticket_5952

Ticket #5952: Simplify redundant parentheses in pointer variable declarations
travis: replace kernel check with clang check.

Check clang instead of kernel, which is a lot faster.
Make clang check failure fatal to the build.
travis: add -DCHECK_INTERNAL to the VERIFY=1 job to automatically fetch issues like #5869 via travis, check clang with --exception-handling
travis: make clang check sensitive to internal cppcheck errors.