Test::Harness resets last error

So preserve it immediately after call.

Author: jandubois

t/HttpGetFile.t

@@ -12,10 +12,19 @@ END { 1 while unlink $tmpfile; }
 #   set PERL_WIN32_INTERNET_OK=1
 plan tests => $ENV{PERL_WIN32_INTERNET_OK} ? 6 : 4;
 
-ok(Win32::HttpGetFile('nonesuch://example.com', 'NUL:'), "", "'nonesuch://' is not a real protocol");
-ok(Win32::GetLastError(), '12006', "correct error code for unrecognized protocol");
-ok(Win32::HttpGetFile('http://!#@!&@$', 'NUL:'), "", "invalid URL");
-ok(Win32::GetLastError(), '12005', "correct error code for invalid URL");
+# On Cygwin the test_harness will invoke additional Win32 APIs that
+# will reset the Win32::GetLastError() value, so capture it immediately.
+my $LastError;
+sub HttpGetFile {
+    my $ok = Win32::HttpGetFile(@_);
+    $LastError = Win32::GetLastError();
+    return $ok;
+}
+
+ok(HttpGetFile('nonesuch://example.com', 'NUL:'), "", "'nonesuch://' is not a real protocol");
+ok($LastError, '12006', "correct error code for unrecognized protocol");
+ok(HttpGetFile('http://!#@!&@$', 'NUL:'), "", "invalid URL");
+ok($LastError, '12005', "correct error code for invalid URL");
 
 if ($ENV{PERL_WIN32_INTERNET_OK}) {
     # The digest for version 0.57 should obviously stay the same even after new versions are released