+#ifdef STAT_STATVFS
+/* Return true if statvfs works. This is false for statvfs on systems
+ with GNU libc on Linux kernels before 2.6.36, which stats all
+ preceding entries in /proc/mounts; that makes df hang if even one
+ of the corresponding file systems is hard-mounted but not available. */
+# if ! (__linux__ && (__GLIBC__ || __UCLIBC__))
+/* The FRSIZE fallback is not required in this case. */
+# undef STAT_STATFS2_FRSIZE
+static int statvfs_works (void) { return 1; }
+# else
+# include <string.h> /* for strverscmp */
+# include <sys/utsname.h>
+# include <sys/statfs.h>
+# define STAT_STATFS2_BSIZE 1
+
+static int
+statvfs_works (void)
+{
+ static int statvfs_works_cache = -1;
+ struct utsname name;
+ if (statvfs_works_cache < 0)
+ statvfs_works_cache = (uname (&name) == 0
+ && 0 <= strverscmp (name.release, "2.6.36"));
+ return statvfs_works_cache;
+}
+# endif
+#endif
+
+