build: Remove two build system hacks

 * Add a (env) variable to enable contrib debugging
 * Remove a hack that caused every packages to be recomplied

Refs #63305

Change-Id: I82ace4786538a26adca3c99538b5c7c0b5e0b03c

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

@@ -121,11 +121,14 @@ function build_contrib {
         ../bootstrap
         # list dependencies that aren't detected by contrib
         make list
-        # FIXME: this is a hack until we remove all libcommoncpp.so linked libs on Jenkins
-        make .zrtpcpp
+
         # FIXME: this is very slow but it's the best we can do until we migrate
         # to a builder with more up to date packages
+        if [ "$DEBUG_CONTRIB" != "" ]; then
             make
+        else
+            make -j
+        fi
         popd
     else
         # We're on 1.4.x