Debian packager's wishlist

While pacakging libstrangle for Debian, a few things have arisen that could be fixed upstream (here) for better and easier packaging:

• If possible, use standard Vulkan headers. Currently libstrangle uses functions that are not included in the vulkan headers packaged in Debian's libvulkan-dev.
• Make CFLAGS and CXXFLAGS overridable – basically, they shouldn't include the flags required for building, like includes.
• Provide proper copyright and license information on the screenshot in the repo.
• Provide manpages for strangle and stranglevk.
• Release a new version with the improvements.

Apart from the last one, these are in descending order of importance. I'll wait a bit for comments before I start opening the proper individual issues.