Ignore artifacts produced by IDEs such as Embarcadero RAD Studio,
JetBrains Fleet, Qt Creator, and possibly others.
Also update the list of artifacts produced by C/C++ workflows and
CMake workflows in Microsoft Visual Studio and Qt Creator.
This is a cherry-pick of commit 10c76f3a1a9096f9b7cf64dd7abf5035e379e47f
from branch 'libpng18'.
Ignore the files and the directories that are typically produced by
text editors, development tools, development environments, etc.
This is a cherry-pick of commit 050aa7bb936c8889a41942b0b83f5db8582bce17
from branch 'libpng18'.
Bring the auto-generated scripts up to date with the autoconf upgrade
from version 2.71 to version 2.72.
Make the .gitignore exclusions better tailored to the autoconf- and
configure-generated artifacts.
