<p><b>@mlschroe</b> commented on this pull request.</p>

<hr>

<p>In <a href="https://github.com/rpm-software-management/rpm/pull/786#discussion_r301983552">doc/manual/macros</a>:</p>
<pre style='color:#555'>> +Frequently used conditionally expanded macros are e.g.
+Define a macro if it is not defined:
+\verbatim
+%{?!with_python3: %global with_python3 1}
+\endverbatim
+A macro that is expanded to 1 if "with_python3" is defined and 0 otherwise:
+\verbatim
+%{?with_python3:1}%{!?with_python3:0}
+\endverbatim
+or shortly
+\verbatim
+0%{!?with_python3:1}
+\endverbatim
+
+%"{?macro_name}" is a shortcut for "%{?macro_name:%macro_name}" and
+similarly "%{?!macro_name}" is a shortcut for "%{?!marco_name:%macro_name}"
</pre>
<p>That's actually not true: <code>%{?!marco_name}</code> always expands to an empty string:</p>
<pre><code>$ rpm --eval '%{?!xxx}'

$ rpm --eval '%{?!xxx:%xxx}'
%xxx
</code></pre>

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