Make fails on FreeBSD due to execinfo.h
Due to: http://www.gnu.org/software/gnulib/manual/html_node/execinfo_002eh.html
The header is missing from the gnu library on non-linux platforms and needs to be linked to.
I've included a patch for CMakeLists.txt, it compiles properly on FreeBSD and it detects the built-in library on Linux (but I couldn't get past the Qt4.4 test there, so it still needs a compilation test).
Also, the following can be replaced in the code:
#if not defined(Q_OS_WIN32) && not defined(MAC_10_4_SDK)
But I haven't done that yet.
Fixing BR #295 - Autobacktraces are limited to Linux now.
Mac OS has it's own crashhandler and BSD seems to lack execinfo.h