regex.c is removed during execution of gmake distclean

[Zube]

Tested on a Solaris 8 machine, fully patched.  gcc 3.4.3, gmake 3.80.

gmake distclean 

executed in the findutils 4.2.18 (and possibly earlier 4.2.x) source root 
causes regex.c in gnulib/lib to be deleted.

To reproduce:

./configure in source root
(optional) gmake
(optional) gmake install
gmake distclean

***

...
gmake[1]: Leaving directory `/stat/src/findutils/findutils-4.2.18/gnulib'
Making distclean in .
gmake[1]: Entering directory `/stat/src/findutils/findutils-4.2.18'
test -z "gnulib/lib/regex.c" || rm -f gnulib/lib/regex.c

***

If one tries to build findutils again (starting with ./configure), the build 
fails because it cannot find regex.c.

Cheers,
Zube