Fix inconsistent configure data for --with-ssl

This inconsistency was showing up after an autoreconf.

Reported-by: Antonin Houska
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/47255.1613716807@antos

configure.ac

@@ -1234,7 +1234,7 @@ if test "$with_ssl" = openssl ; then
   # thread-safety. In 1.1.0, it's no longer required, and CRYPTO_lock()
   # function was removed.
   AC_CHECK_FUNCS([CRYPTO_lock])
-  AC_DEFINE([USE_OPENSSL], 1, [Define to 1 if you have OpenSSL support.])
+  AC_DEFINE([USE_OPENSSL], 1, [Define to 1 to build with OpenSSL support. (--with-ssl=openssl)])
 elif test "$with_ssl" != no ; then
   AC_MSG_ERROR([--with-ssl must specify openssl])
 fi

src/include/pg_config.h.in

@@ -899,7 +899,7 @@
 /* Define to select named POSIX semaphores. */
 #undef USE_NAMED_POSIX_SEMAPHORES
 
-/* Define to build with OpenSSL support. (--with-ssl=openssl) */
+/* Define to 1 to build with OpenSSL support. (--with-ssl=openssl) */
 #undef USE_OPENSSL
 
 /* Define to 1 to build with PAM support. (--with-pam) */