+# Why use the aux file and not the PDF, which is what we really care
+# about? The pdflatex tool currently embeds the creation/modification
+# time into the PDF, so every new version will differ from the last,
+# making comparisons meaningless. This is fixed in pdftex v1.40.17
+# thanks to Debian's SOURCE_DATE_EPOCH initiative. When that version
+# of pdflatex makes it into TeX Live 2016, we can replace this junk
+# with something smarter
+#