Fix detection of OpenSSL built w/o deprecated features support (squid…

…-cache#470)

SSL_library_init() is deprecated since OpenSSL v1.1 and is absent in
OpenSSL built without deprecated features. Several distributions (e.g.
Homebrew) ship OpenSSL built without deprecated features.

configure.ac

@@ -1357,7 +1357,7 @@ if test "x$with_openssl" = "xyes"; then
     AC_CHECK_LIB(crypto,[CRYPTO_new_ex_data],[LIBOPENSSL_LIBS="-lcrypto $LIBOPENSSL_LIBS"],[
       AC_MSG_ERROR([library 'crypto' is required for OpenSSL])
     ],$LIBOPENSSL_LIBS)
-    AC_CHECK_LIB(ssl,[SSL_library_init],[LIBOPENSSL_LIBS="-lssl $LIBOPENSSL_LIBS"],[
+    AC_CHECK_LIB(ssl,[SSL_CTX_new],[LIBOPENSSL_LIBS="-lssl $LIBOPENSSL_LIBS"],[
       AC_MSG_ERROR([library 'ssl' is required for OpenSSL])
     ],$LIBOPENSSL_LIBS)
   ])