*printf: Avoid a dialog during 'configure' with MSVC in debug mode. Suggested by Paul Harris <harris.pc@gmail.com> in <https://lists.gnu.org/archive/html/bug-gettext/2024-04/msg00005.html>. * m4/printf.m4 (gl_PRINTF_DIRECTIVE_N): In the test program, include <crtdbg.h> and disable the MSVC reporting for assertion failures.