diff --git a/ci/Makefile b/ci/Makefile
index 03799924b430cc27d92fdb48e68a43ee62aa8d2c..577b130d2f790330dcbb975808fb0a0d6e5a0bb4 100644
--- a/ci/Makefile
+++ b/ci/Makefile
@@ -216,12 +216,15 @@ ci-run-command@%: ci-prepare-tree
 	$(CI_ENGINE) run $(CI_ENGINE_ARGS) $(CI_IMAGE_PREFIX)$*$(CI_IMAGE_TAG) \
 		/bin/bash -c ' \
 		$(CI_USER_HOME)/prepare || exit 1; \
+		if test "$$PKG_CONFIG_LIBDIR"; then \
+			pkgconfig_env="PKG_CONFIG_LIBDIR=$$PKG_CONFIG_LIBDIR"; \
+		fi; \
 		sudo \
 		  --login \
 		  --user="#$(CI_UID)" \
 		  --group="#$(CI_GID)" \
 		  CONFIGURE_OPTS="$$CONFIGURE_OPTS" \
-		  PKG_CONFIG_LIBDIR="$$PKG_CONFIG_LIBDIR" \
+		  $$pkgconfig_env \
 		  CI_CONT_SRCDIR="$(CI_CONT_SRCDIR)" \
 		  CI_CONT_BUILDDIR="$(CI_CONT_BUILDDIR)" \
 		  CI_SMP="$(CI_SMP)" \