darwinssl: Avoid parsing certificates when not in verbose mode

The information extracted from the server certificates in step 3 is only
used when in verbose mode, and there is no error handling or validation
performed as that has already been done. Only run the certificate
information extraction when in verbose mode and libcurl was built with
verbose strings.

Closes https://github.com/curl/curl/pull/1246

lib/vtls/darwinssl.c

@@ -219,6 +219,7 @@ static OSStatus SocketWrite(SSLConnectionRef connection,
   return ortn;
 }
 
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
 CF_INLINE const char *SSLCipherNameForNumber(SSLCipherSuite cipher)
 {
   switch(cipher) {
@@ -776,6 +777,7 @@ CF_INLINE const char *TLSCipherNameForNumber(SSLCipherSuite cipher)
   }
   return "TLS_NULL_WITH_NULL_NULL";
 }
+#endif /* !CURL_DISABLE_VERBOSE_STRINGS */
 
 #if CURL_BUILD_MAC
 CF_INLINE void GetDarwinVersionNumber(int *major, int *minor)
@@ -2037,9 +2039,11 @@ darwinssl_connect_step2(struct connectdata *conn, int sockindex)
   }
 }
 
-static CURLcode
-darwinssl_connect_step3(struct connectdata *conn,
-                        int sockindex)
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+/* This should be called during step3 of the connection at the earliest */
+static void
+show_verbose_server_cert(struct connectdata *conn,
+                         int sockindex)
 {
   struct Curl_easy *data = conn->data;
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
@@ -2051,9 +2055,9 @@ darwinssl_connect_step3(struct connectdata *conn,
   CFIndex i, count;
   SecTrustRef trust = NULL;
 
-  /* There is no step 3!
-   * Well, okay, if verbose mode is on, let's print the details of the
-   * server certificates. */
+  if(!connssl->ssl_ctx)
+    return;
+
 #if CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS
 #if CURL_BUILD_IOS
 #pragma unused(server_certs)
@@ -2150,6 +2154,23 @@ darwinssl_connect_step3(struct connectdata *conn,
     CFRelease(server_certs);
   }
 #endif /* CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS */
+}
+#endif /* !CURL_DISABLE_VERBOSE_STRINGS */
+
+static CURLcode
+darwinssl_connect_step3(struct connectdata *conn,
+                        int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+
+  /* There is no step 3!
+   * Well, okay, if verbose mode is on, let's print the details of the
+   * server certificates. */
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+  if(data->set.verbose)
+    show_verbose_server_cert(conn, sockindex);
+#endif
 
   connssl->connecting_state = ssl_connect_done;
   return CURLE_OK;