test-copy-file build error on CentOS 6

[Tom G. Christensen]

Hello,

I just noticed that I am unable to build a gnulib snapshot with tests on 
CentOS 6:

gcc -std=gnu99  -g -O2 -Wall   -o test-copy-file test-copy-file.o 
../gllib/libgnu.a -lacl  -lm -lm -lm -lm -lm -lm -lm -lm -lm -lm -lm
../gllib/libgnu.a(gettime.o): In function `gettime':
/home/tgc/projects/gnulib/build/gllib/gettime.c:36: undefined reference 
to `clock_gettime'


The last commit to build successfully was e48f55fd7.

-tgc