jenkins: only use contrib for iax

Rationale: Ideally we shouldn't use contrib at all on deb-based systems, but
IAX is an important albeit unpackaged feature.

Refs #56654

Change-Id: I43fd98dd88d607456b355c44232e74e266d22730

tools/build-system/hudson-sflphone-script.sh

@@ -119,9 +119,11 @@ function build_contrib {
         mkdir -p native
         pushd native
         ../bootstrap
-        # list dependencies which will be added
+        # list dependencies that aren't detected by contrib
         make list
-        make
+        # XXX: only build iax since it's not packaged, we don't want contrib
+        # for anything else
+        make .iax
         popd
     else
         # We're on 1.4.x