The xstr(1) program is still maintained in the NetBSD distribution.
It's not a part of the C compiler - it's much more akin to a C
pre-processor:
http://man.netbsd.org/7.0/usr/share/man/html1/xstr.html
See also mkstr(1):
http://man.netbsd.org/7.0/usr/share/man/html1/mkstr.html
As ham-handed as these tools are, they can be used for input to
manual programmer string storage reduction.
Erik <fair(a)netbsd.org>