contrib/chg/util.h

hghave: add cvsnt

cvsnt is a maintained commercial fork of cvs
https://en.wikipedia.org/wiki/CVSNT

It is possible to build a version of it from sources (github),
it requires libpcre and libltdl (libtool).

We already have a test that relates to cvsnt:
test-convert-cvsnt-mergepoints.t

cvsnt installs: cvs, cvslockd, cvsnt, cvsscript

I think we should definitely have a check for cvsnt because it makes
the version checks for cvs make a lot more sense.

When I use the version I built, cvs --version says:

"""
Concurrent Versions System (CVSNT) 2.5.05 (Gan) Build 3744 (Suite) (client/server)

CVSNT 2.5.05 (Apr  4 2016) Copyright (c) 2008 March Hare Software Ltd.
see http://www.march-hare.com/cvspro


CVS Copyright (c) 1989-2001 Brian Berliner, david d `zoo' zuhn,

Jeff Polk, and other authors
CVSNT Copyright (c) 1999-2008 Tony Hoyle and others
see http://www.cvsnt.org

Commercial support and training provided by March Hare Software Ltd.
see http://www.march-hare.com/cvspro

CVSNT may be copied only under the terms of the GNU General Public License v2,
a copy of which can be found with the CVS distribution.

The CVSNT Application API is licensed under the terms of the
GNU Library (or Lesser) General Public License.

Specify the --help option for further information about CVS
"""

/*
 * Utility functions
 *
 * Copyright (c) 2011 Yuya Nishihara <[e-mail]>
 *
 * This software may be used and distributed according to the terms of the
 * GNU General Public License version 2 or any later version.
 */

#ifndef UTIL_H_
#define UTIL_H_

#ifdef __GNUC__
#define PRINTF_FORMAT_ __attribute__((format(printf, 1, 2)))
#else
#define PRINTF_FORMAT_
#endif

void abortmsg(const char *fmt, ...) PRINTF_FORMAT_;
void abortmsgerrno(const char *fmt, ...) PRINTF_FORMAT_;

void enablecolor(void);
void enabledebugmsg(void);
void debugmsg(const char *fmt, ...) PRINTF_FORMAT_;

void *mallocx(size_t size);
void *reallocx(void *ptr, size_t size);

int runshellcmd(const char *cmd, const char *envp[], const char *cwd);

#endif  /* UTIL_H_ */