Debugger: Use LD_PRELOAD to load debugging helper.
on UNIX. Either set the LD_PRELOAD environment variable
using a gdb command or have the TermGdbAdapter set the
variable for the debuggee. For the remote adapter,
switch on toolchain. dlopen() is a fallback for
platforms where it is not supported and attaching
to running processes. Fixes a crash with gdb 7.0
(and spurious gdb 6.8 crashes with dlopen()).
Reviewed-by: hjk <qtc-committer@nokia.com>
(cherry picked from commit
10e07e01c73da7da305346eab0c4e998a6d2e164)