curl: Apple SecTrust legacy path accepts untrusted certificates on pre-10.14 macOS/iOS when built with USE_APPLE_SECTRUST

Summary: When libcurl is built with USEAPPLESECTRUST and runs on Apple OS versions that lack SecTrustEvaluateWithError macOS 10.14 / iOS 12, the legacy verification path miscompares OSStatus to SecTrustResultType and never checks the SecTrust result. This can cause untrusted certificates to be...