test-suite: fixed tests on Cygwin

configure.ac

@@ -346,6 +346,9 @@ gnu*)
 ;;
 esac
 
+AM_CONDITIONAL([CYGWIN_TARGET], [[test "x$os_is_windows" = "xyes" && \
+                                  test "x${os_is_native_w32}" != "xyes"]])
+
 AC_ARG_WITH([threads],
    [AS_HELP_STRING([--with-threads=LIB],[choose threading library (posix, w32, auto) [auto]])],
    [], [with_threads='auto'])

src/microhttpd/Makefile.am

@@ -166,6 +166,10 @@ endif
 
 TESTS = $(check_PROGRAMS)
 
+# Do not test trigger of select by shutdown of listen socket
+# on Cygwin as this ability is deliberately ignored on Cygwin
+# to improve compatibility with core OS.
+if !CYGWIN_TARGET
 if HAVE_LISTEN_SHUTDOWN
 check_PROGRAMS += \
   test_shutdown_select \
@@ -175,6 +179,7 @@ check_PROGRAMS += \
   test_shutdown_select_ignore \
   test_shutdown_poll_ignore
 endif
+endif
 
 test_start_stop_SOURCES = \
   test_start_stop.c