On line 336 of the configure script '-n' is passed to echo.
Since POSIX echo doesn't support any arguments,
'-n' is treated as a regular string.
This results in ```MCONFIG:1: *** missing separator. Stop.```, on execution of make.
The easiest solution would be to merge date into the same echo command:
echo '# Generated by configure (confgen version 2) on' $(date)
I don't particularly approve of using sed in this way, but it could be used to resolve the issue, as happens in some other ebuilds. For example:
sed -i -e 's/^\([[:space:]]*\)echo -n /\1printf %s /' configure || die
Created attachment 681796 [details, diff]
Here's a patch, anyway.