Consolidate the X11_WMCLASS and WAYLAND_WMCLASS envvars into one SDL_HINT_APP_ID hint. This hint serves the same purpose on both windowing systems to allow desktop compositors to identify and group windows together, as well as associate applications with their desktop settings and icons.
The common code for retrieving the value is now consolidated under core/unix/SDL_appid.c as it's common to *nix platforms, and the value is now retrieved at window creation time instead of being cached by the video driver at startup so that changes to the hint after video initialization and before window creation will be seen, as well as to accommodate cases where applications want to use different values for different windows.
I updated .clang-format and ran clang-format 14 over the src and test directories to standardize the code base.
In general I let clang-format have it's way, and added markup to prevent formatting of code that would break or be completely unreadable if formatted.
The script I ran for the src directory is added as build-scripts/clang-format-src.sh
This fixes:
#6592#6593#6594
I ran this script in the include directory:
```sh
sed -i '' -e 's,#include "\(SDL.*\)",#include <SDL3/\1>,' *.h
```
I ran this script in the src directory:
```sh
for i in ../include/SDL3/SDL*.h
do hdr=$(basename $i)
if [ x"$(echo $hdr | egrep 'SDL_main|SDL_name|SDL_test|SDL_syswm|SDL_opengl|SDL_egl|SDL_vulkan')" != x ]; then
find . -type f -exec sed -i '' -e 's,#include "\('$hdr'\)",#include <SDL3/\1>,' {} \;
else
find . -type f -exec sed -i '' -e '/#include "'$hdr'"/d' {} \;
fi
done
```
Fixes https://github.com/libsdl-org/SDL/issues/6575
Add a new flag to avoid suppressing EINTR in SDL_IOReady(). Pass the
flag in WaitEventTimeout() to ensure that a SIGINT will wake up
SDL_WaitEvent() without another event coming in.
tomwardio
HAVE_POLL is correctly defined in SDL_config.h when running configure. However, in the only place where it's used, it's undefined at the start of the file.
