GDB, the GNU Project debugger, allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed.
ChangeLog Makefile.in README VERSION aclocal.m4 bindtextdom.c config.h.in config.intl.in configure configure.ac dcgettext.c dcigettext.c dcngettext.c dgettext.c dngettext.c eval-plural.h explodename.c finddomain.c gettext.c gettextP.h gmo.h hash-string.h intl-compat.c l10nflist.c libgnuintl.h loadinfo.h loadmsgcat.c localcharset.c localcharset.h locale.alias localealias.c localename.c log.c ngettext.c osdep.c plural-exp.c plural-exp.h plural.c plural.y relocatable.c relocatable.h textdomain.c