Git Merge Request #5: fix: vim cscope test was failing on macOS Monterey (with M1 processor) (open)

Failing Vim cscope test in Vim repo (latest in git) prior to this change:

$ cd vim/src/testdir
$ make test_cscope
...snip...
From test_cscope.vim:
Executed Test_cscopeWithCscopeConnections()        in   1.125674 seconds
Executed Test_cscope_add_dir()                     in   0.165424 seconds
Executed Test_cscopequickfix()                     in   0.000207 seconds
Executed Test_withoutCscopeConnection()            in   0.000162 seconds
Executed 4 tests                         in   1.315866 seconds
2 FAILED:
Found errors in Test_cscopeWithCscopeConnections():
Caught exception in Test_cscopeWithCscopeConnections():
Vim(cscope):E262: Error reading cscope connection 0 @ command
line..script /Users/dope/sb/vim/src/testdir/runtest.vim[459]..function
RunTheTest[44]..Test_cscopeWithCscopeConnections, line 36
Found errors in Test_cscope_add_dir():
command line..script
/Users/dope/sb/vim/src/testdir/runtest.vim[459]..function
RunTheTest[44]..Test_cscope_add_dir line 11: Expected 3 but got 4
command line..script
/Users/dope/sb/vim/src/testdir/runtest.vim[459]..function
RunTheTest[44]..Test_cscope_add_dir line 14: Pattern '^ 0
\\d\\+.*Xcscopedir/cscope.out\\s\\+<none>$' does not match ' 0 20898
/Users/dope/sb/vim/src/testdir/Xcscope.out  <none>'
make: *** [Makefile:66: test_cscope] Error 1

Comparing with Linux x86_64 where Vim cscope test was passing,
I noticed that the difference came from BUFSIZE which was 8192
on Linux and 1024 on macOS. Using a buffer size of 8192 on
all platforms made it work on macOS. However, it's still unclear
why Vim test failed with BUFSIZE being 1024. This fix may be
hiding another bug, so it should be investigated further.

[Hans-Bernhard Broeker]

The bufsize change cannot reasonably be the cause here. BUFSIZ is 1024 on some other platforms, too, where cscope has worked just fine for decades.