fsusage: port to MacOS X 10.7 with 4 TiB file systems * m4/fsusage.m4 (gl_FILE_SYSTEM_USAGE): Reject statvfs implementations that use only 32 bits to count blocks. On typical hosts with 1024-byte blocks, this fails with file systems as small as 4 TiB. Problem reported by Herb Wartens <http://debbugs.gnu.org/9140> and this should also fix a similar problem reported by Tim Spriggs <http://debbugs.gnu.org/7355>.