Given following log snippets, their explanation, and nothing else, explain what failure, if any, occurred during build of this package.

  Snippets are in a format of [X] : [Y], where [X] is a log snippet, and [Y] is the explanation.

  Snippets are delimited with '================'.

  Drawing on information from all snippets, provide a concise explanation of the issue and recommend a solution.

  Explanation of the issue, and recommended solution, should take a handful of sentences.

  Snippets:

  [stdout: Could not parse spec file with error: can't parse specfile
stderr: error: line 1: Unknown tag: ?# Cross-distribution SLiM RPM spec.]: [This is the standard output and standard error for the rpkg command that was used to build the package.]
=============
[Copr build error: error: line 1: Unknown tag: ?# Cross-distribution SLiM RPM spec.]: [It is the Copr build error summary.]

Issue: The build failed because the rpkg command failed, due to being unable to parse the specfile.
Resolution: Correct the "Unknown tag", which was actually a comment at the beginning of the RPM specfile.