build: add die.h; avoid new warnings from GCC 7

* src/die.h (die): New file/function from grep.
Note: we expect this file to migrate to gnulib.
* src/csplit.c: Include die.h.
(check_format_conv_type): Use die in place of error-nonzero;break;
* src/install.c (strip): Likewise.
* src/nl.c (proc_text): Likewise.  This also suppresses a new warning
from GCC 7's -Werror=strict-overflow.
* src/tail.c (parse_options): Likewise.
* src/basename.c (main): Adjust "fall through" comment
so that GCC 7's -Wimplicit-fallthrough honors it.
* src/cp.c (main): Add a "fall through" comment.
* src/ls.c (gobble_file): Likewise.
(get_funky_string): Adjust a "fall through" comment so it is
recognized.
* cfg.mk (exclude_file_name_regexp--sc_system_h_headers): Add die.h
to this list of exempt src/*.h files.

1 files changed, 31 insertions, 0 deletions

diff --git a/src/die.h b/src/die.h
new file mode 100644
index 000000000..f64ab349f
--- /dev/null
+++ b/src/die.h
@@ -0,0 +1,31 @@
+/* Report an error and exit.
+   Copyright 2016 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+#ifndef DIE_H
+# define DIE_H
+
+# include <error.h>
+# include <stdbool.h>
+# include <verify.h>
+
+/* Like 'error (STATUS, ...)', except STATUS must be a nonzero constant.
+   This may pacify the compiler or help it generate better code.  */
+# define die(status, ...) \
+  verify_expr (status, (error (status, __VA_ARGS__), assume (false)))
+
+#endif /* DIE_H */