The ARM926EJ-S Technical Reference Manual states:
> You can only access CP15 registers with MRC and MCR instructions in a
> privileged mode. CDP, LDC, STC, MCRR, and MRRC instructions, and unprivileged
> MRC or MCR instructions to CP15 cause the Undefined instruction exception to
> be taken.
Furthermore, `MCR p15, 0, <Rd>, c7, c10, 5` (later called Data Memory Barrier)
is not specified for the ARM926. Thus, SDL should not use these cache
instructions on ARMv5.
Appropriate CPU directive can be used in #pragma aux so that it is not
necessary to hardcode instruction bytes.
(cherry picked from commit 507fc462db1ede9f3ca2c581809a7f1492ac1ff5)
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