ACX_BUGURL has [case "$withval" in yes) AC_MSG_ERROR([bug URL not specified]) ;; no) REPORT_BUGS_TO=""; REPORT_BUGS_TEXI="" ;; *) REPORT_BUGS_TO="<$withval>" REPORT_BUGS_TEXI="@uref{`echo $withval | sed 's/@/@@/g'`}" ;; esac], REPORT_BUGS_TO="<$1>" REPORT_BUGS_TEXI="@uref{$1}"
It assumes there is no @ in $1. Shouldn't be REPORT_BUGS_TEXI="@uref{`echo $1 | sed 's/@/@@/g'`}" H.J.