Sorry, but I don't really understand your patch. With it, it would seem that _AM_FILESYSTEM_TIMESTAMP_RESOLUTION is only called if the build environment is not "sane", i.e., a created file is not newer than configure. Is that right? (That embedded shell construct is hard to grok.)
is in _AM_FILESYSTEM_TIMESTAMP_RESOLUTION, whose sole purpose is to determine a variable am_cv_filesystem_timestamp_resolution. The sole use of this variable is in AM_SANITY_CHECK, The timestamp resolution also used in Automake's t/ax/test-defs.in (->.sh), and Automake's configure.ac, aka MTIME_RESOLUTION. With your patch, how does it ever get defined? Did you intend that Automake's configure.ac would then explicitly call _AM_FILESYSTEM_TIMESTAMP_RESOLUTION (in which case it should probably be renamed without a leading underscore), or am I misunderstanding the whole thing? (Quite likely.) --thanks, karl.