Port file-system-info to non-Microsoft

* admin/merge-gnulib (GNULIB_MODULES): Add fsusage.
* doc/emacs/files.texi (Directories): Remove documentation of
now-obsolete directory-free-space-program and
directory-free-space-args.
* etc/NEWS: Mention change.
* etc/PROBLEMS: Slow df is no longer a problem.
* lib/fsusage.c, lib/fsusage.h, m4/fsusage.m4:
New files, copied from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lisp/dired.el (dired-free-space-program)
(dired-free-space-args): These aliases are now obsolete.
* lisp/files.el (directory-free-space-program)
(directory-free-space-args): Now obsolete.
(get-free-disk-space): Just call file-system-info instead
of the now-obsolete directory-free-space-program.
* nt/gnulib-cfg.mk (OMIT_GNULIB_MODULE_fsusage): New macro.
* src/fileio.c: Include fsusage.h.
(blocks_to_bytes, Ffile_system_info) [!DOS_NT]: New functions.
(syms_of_fileio) [!DOS_NT]: Defsubr file-system-info.

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/fsusage.h b/lib/fsusage.h
new file mode 100644
index 00000000000..f78edc6a0cb
--- /dev/null
+++ b/lib/fsusage.h
@@ -0,0 +1,40 @@
+/* fsusage.h -- declarations for file system space usage info
+
+   Copyright (C) 1991-1992, 1997, 2003-2006, 2009-2017 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 of the License, 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, see <https://www.gnu.org/licenses/>.  */
+
+/* Space usage statistics for a file system.  Blocks are 512-byte. */
+
+#if !defined FSUSAGE_H_
+# define FSUSAGE_H_
+
+# include <stdint.h>
+# include <stdbool.h>
+
+struct fs_usage
+{
+  uintmax_t fsu_blocksize;      /* Size of a block.  */
+  uintmax_t fsu_blocks;         /* Total blocks. */
+  uintmax_t fsu_bfree;          /* Free blocks available to superuser. */
+  uintmax_t fsu_bavail;         /* Free blocks available to non-superuser. */
+  bool fsu_bavail_top_bit_set;  /* 1 if fsu_bavail represents a value < 0.  */
+  uintmax_t fsu_files;          /* Total file nodes. */
+  uintmax_t fsu_ffree;          /* Free file nodes. */
+};
+
+int get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp);
+
+#endif