On cygwin, using only the additional "--wish-rsh=rsh" parameter to ./configure, "make check" passes all the tests (some are skipped) except for "default-acls". This is a copy of test.log:
Testing for symlinks using 'test -h'
sending incremental file list
created directory /tmp/local/unixutil/.tmp/rsync/rsync-3.0.0pre1/testtmp/default-acls/da777/to
delta-transmission disabled for local transfer or --whole-file
total: matches=0 hash_hits=0 false_alarms=0 data=16
sent 168 bytes received 53 bytes 147.33 bytes/sec
total size is 16 speedup is 0.07
permissions: rwx------ on /tmp/local/unixutil/.tmp/rsync/rsync-3.0.0pre1/testtmp/default-acls/da777/to
should be: rwxrwxrwx
failed test Target da777
The complete build is OK under Solaris 2.8.
The original report was against 3.0.0pre1.
The same behaviour also occurs with 3.0.0pre2.
I don't have access to an MS Win box to test this, but I imagine that that this is just showing that MS ACLs work differently.
Waiting for more information on this, i suggest that you "SKIP" the test in the Cygwin case.
This test has been made to auto-skip in the latest git source (and a couple other fixes and improvements made for Cygwin, including getting xattrs supported). The Cygwin CI builds are doing well on GitHub Actions.
The details behind this particular failure are that the test expects to be able to turn off all default-ACL mode changes by disabling the default-ACLs on one parent directory. However, under Cygwin new directories withing that parent directory still get created with a default-ACL rule that causes the mode of new files to not be what the test expects. Thus, just skipping that test seems to be the best solution.