how to know if a rpm has support for something

[ESGLinux]

Hello,

I have a general question and a particular question.

I begin with the particular question. I want to know if this rpm:
rpm -qi postfix
Name        : postfix                      Relocations: (not relocatable)
Version     : 2.3.3                             Vendor: Red Hat, Inc.
Release     : 2.1.el5_2                     Build Date: lun 11 ago 2008
13:45:07 CEST
Install Date: mar 12 may 2009 14:02:17 CEST      Build Host:
hs20-bc2-2.build.redhat.com
Group       : System Environment/Daemons    Source RPM:
postfix-2.3.3-2.1.el5_2.src.rpm
Size        : 8332580                          License: IBM Public License
Signature   : DSA/SHA1, jue 14 ago 2008 16:51:20 CEST, Key ID
5326810137017186
Packager    : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>
URL         : http://www.postfix.org
Summary     : Agente de Transporte de Correo Postfix
Description :
Postfix es un Agente de Transporte de Correo (MTA), que soporta LDAP,
SMTP AUTH (SASL), TLS

has mysql and quota support.

and in general, how can I see how was compiled a rpm to know what  it is
built on it and what not. ?

Thanks in advance

ESG