tools/mm-macros: remove ccaaab1c048159611e93a181dde740f49fa12483 says that this is in the codebase because of libsigc++, which is not in the codebase anymore. Neither in base nor in packages. It doesn't seem to be needed by anything else either. GNOME packages have transitioned to using meson, which does not use m4 files. Tested local compile with CONFIG_ALL. No problems seen. Signed-off-by: Rosen Penev <rosenp@gmail.com>