* buildrun.cxx (compile_pass): Add autoconf line for stack trace
test, which defines STAPCONF_KERNEL_STACKTRACE.
* runtime/autoconf-save-stack-trace.c: New file.
* runtime/stack.c : Use STAPCONF_KERNEL_STACKTRACE instead of
tests for kernel configuration and versions.
* runtime/stack-i386.c : ditto
* runtime/stack-x86_64.c : ditto