Improve detection of conf.pri.

unixconf.pri

@@ -1,7 +1,13 @@
 # Generated by the configure file
-# There will be a WARNING during configure that this file wasn't found.
-# This is harmless. During make the file will be found. If not, there will a WARNING again.
-include($$OUT_PWD/../conf.pri)
+# Ignore any WARNING about 'conf.pri' missing during configure. The file should be found during make.
+# If not there will be a WARNING again.
+# The first path is used when the source is being build by packagers (pbuilder/sbuild/etc)
+# The second path is used when you manually run the configure script in the root folder (eg when using qt creator)
+exists($$OUT_PWD/../conf.pri) {
+    include($$OUT_PWD/../conf.pri)
+} else {
+    include(conf.pri)
+}
 
 # COMPILATION SPECIFIC
 !nox:dbus {