$top_srcdir being treated as command in configure for reproducible date

The $top_srcdir variable is being created as a command in lalsuite_build.m4 and not expanded:

./configure: line 6742: top_srcdir: command not found
./configure: line 6742: /gnuscripts/reproducible-date: No such file or directory

as such LAL_CONFIGURE_DATE is not being set:

[root@25d784486f8d .libs]# strings liblal.a | grep LAL_CONFIGURE_DATE
LAL_CONFIGURE_DATE ""
[root@25d784486f8d .libs]#