configure: fix LTTng UST tracing backend detection

The detection program needs to be linked with -ldl to build succesfully
with recent versions of LTTng-UST.

We also need to add -ldl to the libs required to build the LTTng-UST
backend (lttng_ust_libs).

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Message-id: 1480348337-24271-1-git-send-email-francis.deslauriers@efficios.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/configure b/configure
index 5e66828..89df5c4 100755 (executable)
--- a/configure
+++ b/configure
@@ -4305,11 +4305,11 @@ if have_backend "ust"; then
 #include <lttng/tracepoint.h>
 int main(void) { return 0; }
 EOF
-  if compile_prog "" "" ; then
+  if compile_prog "" "-Wl,--no-as-needed -ldl" ; then
     if $pkg_config lttng-ust --exists; then
       lttng_ust_libs=$($pkg_config --libs lttng-ust)
     else
-      lttng_ust_libs="-llttng-ust"
+      lttng_ust_libs="-llttng-ust -ldl"
     fi
     if $pkg_config liburcu-bp --exists; then
       urcu_bp_libs=$($pkg_config --libs liburcu-bp)