Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

Pull request

Fix for a LTTng Userspace Tracer header problem.

# gpg: Signature made Tue 07 Jul 2020 16:10:04 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  tracetool: work around ust <sys/sdt.h> include conflict

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

scripts/tracetool/backend/dtrace.py

@@ -40,6 +40,12 @@ def generate_h_begin(events, group):
     else:
         header = "trace-dtrace.h"
 
+    # Workaround for ust backend, which also includes <sys/sdt.h> and may
+    # require SDT_USE_VARIADIC to be defined. If dtrace includes <sys/sdt.h>
+    # first without defining SDT_USE_VARIADIC then ust breaks because the
+    # STAP_PROBEV() macro is not defined.
+    out('#define SDT_USE_VARIADIC 1')
+
     out('#include "%s"' % header,
         '')