+# If the output PDF exists but the log file does not, then an attempt
+# to "build the log file" (i.e. build the PDF) would do nothing. Thus
+# whenever the log file does not exist, we do a fresh build.
+$(PN).log: $(SRCS)
+ $(MAKE) clean
+ $(MAKE)
+
+# Ensure that there are no overfull or underfull boxes in the output
+# document by parsing the log for said warnings.
+.PHONY: check-boxes
+check-boxes: $(PN).log
+ @! grep -i 'overfull\|underfull' $<
+