gdbserver --wrapper also doesn't work on Cygwin.

Skip the test on Cygwin too.

2013-09-18  Pedro Alves  <palves@redhat.com>

	PR server/15967
	* gdb.server/wrapper.exp: Also return unsupported for Cygwin, and
	change text.

gdb/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2013-09-18  Pedro Alves  <palves@redhat.com>
+
+	PR server/15967
+	* gdb.server/wrapper.exp: Also return unsupported for Cygwin, and
+	change text.
+
 2013-09-18  Yao Qi  <yao@codesourcery.com>
 
 	* gdb.server/wrapper.c: New.

gdb/testsuite/gdb.server/wrapper.exp

@@ -25,8 +25,9 @@ if { [skip_gdbserver_tests] } {
     return 0
 }
 
-if [istarget *-*-mingw*] {
-    unsupported "Command env doesn't exist on Windows."
+if { [istarget *-*-mingw*]
+     || [istarget *-*-cygwin*] } {
+    unsupported "gdbserver does not support --wrapper on this target (PR server/15967)"
     return -1
 }