sage

6d187b15 - gh-37764: ECM-related tests fail after an incremental build

gh-37764: ECM-related tests fail after an incremental build ### TL;DR: This is because setting the default ECMBIN=ecm is only done when using the configure test, but not when skipping the configure test because the spkg is already installed. ### Steps to reproduce: * ecm is not installed in the base os * Sage make distclean && make succeeeds * Tests succeed * re-running ./bootstrap && ./configure && make works * Tests now fail with PermissionError: [Errno 13] Permission denied: '' ### Dependencies See also: * https://github.com/sagemath/sage/pull/37701 * https://github.com/sagemath/sage/pull/37011#issuecomment-2023089743 URL: https://github.com/sagemath/sage/pull/37764 Reported by: Volker Braun Reviewer(s): Matthias Köppe