Add support for generating a systemtap tapset static probes

This introduces generation of a qemu.stp/qemu-system-XXX.stp
files which provides tapsets with friendly names for static
probes & their arguments. Instead of

    probe process("qemu").mark("qemu_malloc") {
        printf("Malloc %d %p\n", $arg1, $arg2);
    }

It is now possible todo

    probe qemu.system.i386.qemu_malloc {
        printf("Malloc %d %p\n", size, ptr);
    }

There is one tapset defined per target arch, for both
user and system emulators.

* Makefile.target: Generate stp files for each target
* tracetool: Support for generating systemtap tapsets
* configure: Check for whether systemtap is available
  with the DTrace backend

Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/configure b/configure
index f8dad3e..2917874 100755
--- a/configure
+++ b/configure
@@ -2203,6 +2203,10 @@
     echo
     exit 1
   fi
+  trace_backend_stap="no"
+  if has 'stap' ; then
+    trace_backend_stap="yes"
+  fi
 fi
 
 ##########################################
@@ -2645,6 +2649,9 @@
 if test "$trace_backend" = "simple"; then
   trace_file="\"$trace_file-%u\""
 fi
+if test "$trace_backend" = "dtrace" -a "$trace_backend_stap" = "yes" ; then
+  echo "CONFIG_SYSTEMTAP_TRACE=y" >> $config_host_mak
+fi
 echo "CONFIG_TRACE_FILE=$trace_file" >> $config_host_mak
 
 echo "TOOLS=$tools" >> $config_host_mak