Redmine #3048: Fix configure --with-libacl.

Apparently AC_CHECK_HEADERS runs the third argument if *any* of the
headers are not found, instead of if none of them are found, so that
logic needs to be outside the loop.
Redmine #4809: Fix several filestat() fields on Windows.

Some are best-effort, like permoct will always be 666 or 444, because
the only non-ACL file attribute on Windows that maps to Unix is the
read-only attribute.
Skip several tests that use inode data on Windows.
Fix several acceptance tests after the introduction of $(G.etc_group).

The main problem is that the path contains redundant '../../' parts
and the test doesn't expect that.

Redmine #4809.
Merge pull request #1571 from kacfengine/configure_with_libacl

Redmine #3048: Fix configure --with-libacl.
Merge pull request #1577 from kacfengine/filestat_windows_fixes

Redmine #4809: Filestat windows fixes + test fixes
Set source=persistent on classes loaded from persistence

Redmine #5017
Introduce PRINTSIZE macro to help declare right-sized buffers.

The size of a buffer needed to safely sprintf() an integral type can
be computed from the sizeof() the type.  Doing so ensures we don't
waste stack space declaring "big enough" buffers that are way bigger
than we actually need; and shall ensure, if we ever port to systems
with bigger integral types, that "big enough" really is.

Made assorted variables more local in the process