Check version of "check" unit test framework

test/civetweb_check.h

@@ -35,7 +35,16 @@
 #pragma warning(disable : 4127)
 #endif
 #include <stdint.h>
+
+/* All unit tests use the "check" framework.
+ * Download from https://libcheck.github.io/check/
+ */
 #include "check.h"
+
+#if (CHECK_MINOR_VERSION < 11)
+#error "CivetWeb unit tests require at least check 0.11.0"
+#endif
+
 #ifdef __clang__
 #pragma clang diagnostic pop
 #endif