Wolfgang Jenkner <wjenkner@inode.at> writes:
> However, bootstrapping emacs-25 (d9ea795, which already contains your
> fix) with

> $ ./configure --without-all --without-x

> in a FreeBSD 9 amd64 jail on my FreeBSD 10 system works fine with cc,
> i.e. gcc 4.2.1.

Confirmed.  On amd64, without X gives a successful build, with it gives the error.

Successful build without X: http://pkg.awarnach.mathstat.dal.ca/data/9amd64-default/2016-02-15_13h30m20s/logs/errors/emacs-devel-25.0.90,2.log*
Unsuccessful build With X:  http://pkg.awarnach.mathstat.dal.ca/data/9amd64-default/2016-02-15_13h54m53s/logs/errors/emacs-devel-25.0.90,2.log

* The package installation errors at the end are unrelated to Emacs.  I just didn't deal with file changes when I testing.