Libretro doens't use gboolean for these but bool, which doesn't have the
same size, causing stack smashes.

This will help printing debug logs when RETRO_DEBUG is set to 1.

This catches SIGSEGV to print the backtrace via g_on_error_stack_trace()
when RETRO_DEBUG is set to 1 instead of running in gdb, speeding up the
runner process with debug log enabled.

This makes them in line with the phrasing that will be used for debug
logs.

Log a critical error when trying to use Direct3D, specifying support
isn't planned.

Instead log the critical error and return the failure.

Instead log the critical error and return the failure.

Otherwise it will always return FALSE starting from the second call.

This will simplify logging debug information.

This helps better know at a glance where the error comes from.

This will help debugging sessions.

This makes debugging easier.

This makes it more clear in the logs why a stack trace is printed, and
it will make finding it easier by acting as a colorful header.

Setter environment commands have const values.

While the values are unlikely to case issues, being careful doesn't
hurt.

No need to wrap it here.

This helps making the type of iterators clearer, and that the final
iterated values aren't used later. If an iterator variable is reused but
not to get the final iterated value, the variable is renamed to avoid
confusion.

This drops RETRO_CORE_DESCRIPTOR_ from the name of some local macros,
making them easier to read.

This makes them less abstract.

This purposefuly doesn't do it for errors as they will later be handled
in a more appropriate way.

Errors should never be piled up.

It makes the code easier to understand.

This isn't needed anymore as since we have a single module per runner
process, we are guaranteed to have different instances of the same
module even if we create multiple RetroCores from it, hence ensuring we
can't have static variable collisions.

This steals a pointer we auto cleanup as the hash table takes possession
of it, solving a double free issue.

Also stop using extensions.

See https://www.khronos.org/registry/EGL/sdk/docs/man/html/eglCreateContext.xhtml