... as discussed in fltk.coredev in thread "RFC: introduce public
config header <FL/fl_config.h>", see:
https://groups.google.com/g/fltkcoredev/c/xLCs1AIXMVo/m/MHZpQggzAQAJ
- Rename abi-version.h to fl_config.h, rename input files,
update dependencies, .gitignore, CMake, configure and Makefiles.
- Include Cairo options in FL/fl_config.h
- Rename FLTK_USE_CAIRO to FLTK_HAVE_CAIROEXT for consistency.
- Include <FL/fl_config.h> in config.h and wherever necessary,
fix include order (move FL/Fl.H to the top) and more.
- Move USE_X11 to fl_config.h and rename to FLTK_USE_X11
- Do not include <config.h> in Cairo demo program which is no
longer required in Cairo programs since FLTK 1.4.0
- remove obsolete svn '$Id$' tags from all source files
- update .fl files and generated files accordingly
- replace 'http://www.fltk.org' URL's with 'https://...'
- replace bug report URL 'str.php' with 'bugs.php'
- remove trailing whitespace
- fix other whitespace errors flagged by Git
- add and/or fix missing or wrong standard headers
- convert tabs to spaces in all source files
The only relevant code changes are in the fluid/ folder where
some .fl files and other source files were used to generate
the '$Id' headers and footers.
