I found it irritating that there was inconsistent usage of tabs and
spaces at the beginning of lines.  So I reformatted the entirety of the
src directory such that all lines that begin with 8 spaces now begin
with tabs, and all lines that begin with 1 tab and 8 spaces now begin
with 2 tabs, and so on.

Here was the bash command I used for future reference (run it about 10 times):

$ find src -name '*.c' -o -name '*.h' | xargs perl -pe 's/^(\t*) {8}/$1\t/' -i

Diff is attached.  It is rather large.