Portability part 1 - C99 printf

printf, sprintf, fprintf etc are now all C99 compliant. All except sprintf, which is now signaled as deprecated. This raises a few warnings about sprintf usage in the build. Some I fix with pull requests that will follow. Some others should be fixed by the respective authors.
Not wild about the second sentence: squash isn't the only good mode of tidy.
Tidy up the commit log using `git rebase -i`.