diff --git a/depends/config.site.in b/depends/config.site.in
index c39975ecdef..f4531830c86 100644
--- a/depends/config.site.in
+++ b/depends/config.site.in
@@ -79,7 +79,7 @@ fi
 if test -n "@CXX@" -a -z "${CXX}"; then
   CXX="@CXX@"
 fi
-PYTHONPATH=$depends_prefix/native/lib/python3/dist-packages:$PYTHONPATH
+PYTHONPATH="${depends_prefix}/native/lib/python3/dist-packages${PYTHONPATH:+${PATH_SEPARATOR}}${PYTHONPATH}"
 
 if test -n "@AR@"; then
   AR=@AR@