fix #592 -- add check for static-linked OpenSSL (#595)

httplib.h

@@ -199,7 +199,7 @@ using socket_t = int;
 #include <openssl/ssl.h>
 #include <openssl/x509v3.h>
 
-#ifdef _WIN32
+#if defined(_WIN32) && defined(OPENSSL_USE_APPLINK)
 #include <openssl/applink.c>
 #endif