Examining the /usr/share/autoconf/m4sugar directory, it appears that there is a frozen m4sh.m4f file.
Looking at the autoconf package, I guess that these are generated by the autoconf-2.63/lib/m4sugar/Makefile, because they are mentioned in the Makefile.am file as follows: nodist_m4sugarlib_DATA = version.m4 m4sugar.m4f m4sh.m4f ## ------------------ ## ## The frozen files. ## ## ------------------ ## m4sugar.m4f: $(m4sugar_m4f_dependencies) m4sh.m4f: $(m4sh_m4f_dependencies) include ../freeze.mk Deleting /usr/share/autoconf/m4sugar/m4sh.m4f causes the updated m4sh.m4 to take effect. It would be better for frozen files to be placed in /var/cache/autoconf and then make used to rebuild them in the event that the m4 sources in /usr/share/autoconf become newer. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org