trace: fix compilation with lttng-ust >= 2.13

trace: fix compilation with lttng-ust >= 2.13

On Fedora 36, with lttng-ust 2.13.1, compilation fails with:

In file included from trace/trace-ust-all.h:49085,
                 from trace/trace-ust-all.c:13:
/usr/include/lttng/tracepoint-event.h:67:10: error: #include expects "FILENAME" or <FILENAME>
   67 | #include LTTNG_UST_TRACEPOINT_INCLUDE
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

In lttng-ust commit 41858e2b6e8 ("Fix: don't do macro expansion in
tracepoint file name") from 2012, starting from lttng-ust 2.1, the API
was changed to expect TRACEPOINT_INCLUDE to be defined as a string.

In lttng-ust commit d2966b4b0b2 ("Remove TRACEPOINT_INCLUDE_FILE
macro"), in 2021, the compatibility macro was removed.

Use the "new" API from 2012, and bump the version requirement to 2.1 to
fix compilation with >= 2.13.

According to repology, all distributions we support have >= 2.1 (centos
8 has oldest with 2.8.1 afaict)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220328084717.367993-2-marcandre.lureau@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>