[libpng16] chore: Clean up the leading blank lines from all source files The leading blank lines are apparently an artefact of an older source control system. They are not required and they look like accidents, because starting a source file with a blank line is not a regular habit of software developers nowadays. This is a cherry-pick of commit 37cc20add8fb5b83bb5299a26cd3b41e0f776017 from branch 'libpng18'. Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>