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:

  [+ /usr/lib/rpm/rpmuncompress /builddir/build/SOURCES/desktop-file-qpa-platform-xcb.patch
+ /usr/bin/patch -p1 -s --fuzz=0 --no-backup-if-mismatch -f
1 out of 1 hunk FAILED -- saving rejects to file res/linux/org.mixxx.Mixxx.desktop.rej
RPM build errors:
error: Bad exit status from /var/tmp/rpm-tmp.Dpx66n (%prep)]: [Build failed in %prep phase on applying desktop-file-qpa-platform-xcb.patch patch.]

Issue: patch tool rejected the patch file. That means that the patch file does not match the unpacked sources.
Resolution: Read the rejected hunk stored in res/linux/org.mixxx.Mixxx.desktop.rej file and compare it to the unpacked sources to be built and to the sources the patch was created from. Then port the patch from the patch' sources to the sources used in the build.