Given that the GTK and WPE ports can be configured with a number of options enabled or disabled at the packager's discretion, we have sometimes found that replicating some build configuration for debugging, or figure out what is going on with a reported issue it would be desirable to be able to know whether certain build options (e.g. USE_OPENJPEG, ENABLE_WEB_RTC, USE_ANGLE_WEBGL, and so on) were enabled. This is particularly important with the WPE port, where embedded deployments may include heavily customized builds that even toggle options which we do not officially support changing (like ENABLE_VIDEO), or where web views may be headless and checking the output from webkit://gpu can be quite hard.
My suggestion here would be to have CMake generate a preprocessor symbol which expands to a string that contains the list of CMake build options which have a non-default value. Listing all would make the list quite long, and we are only really interested in on-default values (we can always check the defaults from the source code). Then, I would add a new webkit_get_version_string() function which would return said string concatenated after the version numbers. Basically, this: const char* webkit_get_version_string(void) { return STRINGIZE(WEBKIT_MAJOR_VERSION) "." STRINGIZE(WEBKIT_MINOR_VERSION) "." STRINGIZE(WEBKIT_MICRO_VERSION) WEBKIT_NONDEFAULT_CMAKE_OPTIONS_STRING; } The WEBKIT_NONDEFAULT_CMAKE_OPTIONS_STRING would be a series of zero or more space-and-option-name items, alphabetically sorted, e.g. " -DENABLE_WEB_RTC=ON -DUSE_ANGLE_WEBGL=OFF -DUSE_AVIF=OFF". This way the output from printing webkit_get_version_string() can be almost copied as-is into a CMake command line. Also I think we would need to always include -DDEVELOPER_MODE=ON and -DENABLE_EXPERIMENTAL_FEATURES=ON in case they are enabled, because they affect the default values of build options.
On ELF targets we could also add a main() symbol to the WebKit library which jsut does “printf("%s\n", webkit_get_version_string())”, which will be ignored when the library is loaded as a dependency for some executable, but which will run if the library is executed as if it were a program. Some libraries have done this kind of thing for decades, for example the GNU C library: % /usr/lib/libc.so.6 | head -1 GNU C Library (GNU libc) stable release version 2.36. % Although we may as well skip this bit. As long as the build options string ends up somewhere in the library, one can always run “strings” on it to find the build options without even running anything.