xv is an ancient but small X graphic file viewer. If you try to compile the latest source (3.10a) on Centos 5, you’ll get the following fatal error message:

In file included from xv.c:11:
xv.h:119 error: conflicting types for 'sys_errlist'

To get a successful compile, simply edit xv.h. Remove all the #defines around ‘include <errno.h>’ (about 4 or 5 lines). Replace with the single line:

include <errno.h>

Type ‘make’ again and your compile should succeed.