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The changeset (or "diff") of each commit between the fork-point and <head>
is compared against each commit between the fork-point and <upstream>.
-The commits are compared with their 'patch id', obtained from
-the 'git patch-id' program.
+The diffs are compared after removing any whitespace and line numbers.
Every commit that doesn't exist in the <upstream> branch
has its id (sha1) reported, prefixed by a symbol. The ones that have