When using the marco WM, and resizing using ALT-Right-drag, calls to
SDL_SetWindowMinimumSize() result in the top-left corner of the
window moving up and to the left (appears to be by the border size).

To prevent this from being a maddening issue under marco, ensure
we only call SDL_SetWindowMinimumSize() once when the minimum size
changes on the window.

Fixes SF ticket 115, thanks Ragnarok!

While we're hear, ensure the minimium maximum window size holds
the original sized window... we're not interested in downscaling.

sdl_getscaling() does not require vstatlock.  Move it out.

Currently useful only in GDI and SDL modes.  The external scaling
method is likely lower CPU utilization and may or may not look
better.

All bitmap drivers now support arbitrary scaling, and the scaling
factor is a double, allowing arbitrary window scaling in all bitmap
modes (making nelgin happy).

While we're here, fix bugs in horizontal interpolation and X window
resizeing.

For graphical modes, this requests that ciolib be initialized in
the specified mode.  For text-based modes (ANSI, Curses, Win32 Console),
this is not used and "current" is used instead.

Pretty sure this is what intptr_t was created for.

This is now simple to implement.

Also, add ciolib_initial_scaling so the initial window can be created
with the appropriate scaling already applied.

We still need a way to specifiy the initial text mode, but these
globals are not the right way.

Move snap logic into bitmap
Move new mode window size logic into bitmap

This caused double-keys on those when numlock was off.  Only the
number keys and period need special NumLock handling.

Fixes bug 108 on SourceForge, thanks nelgin!

Add setwinsize and setwinpos
Move blit from rect into gdi_thread
Add beep support
Add (non-functional) settitle support
Support ciolib scaling in addition to GDI scaling
Add window-size snapping
Support -iG in SyncTERM

GDI is still the second-least preferred mode, so auto mode will only
use it if the windows console somehow fails.  But at least people
can play with it.

Fixes issue on Linux where the window size is constantly updated,
and window rabidly steals focus.

This lock has devolved into a wrapper lock for vstatlock.

Use pthread_once() for init_mouse() instead of a global
Fix some lock issues in cb_drawrect()

When fast scrolling, memmove() takes most of the CPU by far... it
is likely actually worth having each line be a buffer of its own
and just moving the pointers around.  To help with this optimization
in the future, move the screen memmove() bit into a separate function.

Fix a couple warnings while we're here.

This should almost completely remove vstatlock contention in SyncTERM,
which should bring SDL output performance close to X11 performance.

This makes cvstat work as intended, so we no longer need to lock
vstatlock when accessing it since it's only accessed from the
video event thread.

There's still an irritating dependency on vstat for ALT-Enter handling.

When originally created, it was intended to be accessed only by a
single thread, and therefore not need mutex protection, allowing
less code to run with vstatlock held.  Unfortunately, this is not
how it turned out, so cvstat should either be removed, or it should
actually be cleaned up to work as intended.

for an extended time.  Should fix SDL mode slowness.

Only call RenderPresent() if we called RenderCopy().  Should fix
SDL mode flickering.

1) Unreachable return without a lock in sdl_useR_func_ret() (harmless)
2) LOR in handling SDL_USEREVENT
   - vstatlock was obtained inside of win_mutex which should never
     be done... this could (and likely does) result in a deadlock
     when using SDL mode.

sdl_setwinsize() and eliminate another race.

Pass window size in SDL_USEREVENT_SETVIDMODE
- Fixes race condition where SDL_WINDOWEVENT_RESIZED or
  SDL_WINDOWEVENT_SIZE_CHANGED arraves while
  SDL_USEREVENT_SETVIDMODE is in the queue

Set new scaling based on old scaling multiplier
- Will resize window on mode changes, but tries to keep integer
  multiplier similar.  May break fullscreen modes, dunno.

Have aspect_fix() return higher rather than lower
- This may make it the same as aspect_correct(), but I'm too lazy
  to figure that out.

Add additional stderr debugging.
Don't try to correct the aspect ratio of the window.

While we're doing that, actually use it in SyncTERM so the offline
scrollback retains fonts.

Also, fix an issue where the current mode would be updated with
the custom parameters when you changed them.

Finally, remove some unused variables.

Now that ALT-Up/Down no longer have an effect on window size, they
can go back to their previous bindings of changing the emulated
output speed.

At the same time, remove AltGr support from keysym parsing since it
should be properly handled by the text input stuff now.

People are used to thinking about the aspect ratio of displays and
used to not thinking at all about that of pixels.  Most of the modes
are simplt 4:3 modes and the text area is the entire window.  The
only oddball here is the Commodore 64 and 128 40-column modes.
Because they have a border around them that's wider on the sides than
the top/bottom, the display aspect ratio is actually narrower than
a normal NTSC screen (6:5).  It seems the PAL version actually has
square pixels, but nobody has asked for a PAL Commodore mode, and I
think that has a different colour palette too so I'm not doing it.

Just to frustrate DigitalMan a bit, the default custom aspect ratio
is now 4:3 (but can be configured).  At present, modifying the custom
mode while *in* the custom modes "works", which no sane person would
want when adjusting the aspect ratio.

Microsoft wants us to use a manifest for this, but I really don't
feel like digging into however one uses manifest files when not
using the Microsoft build files.

Details here: https://docs.microsoft.com/en-us/windows/win32/hidpi/setting-the-default-dpi-awareness-for-a-process

This may solve issue where using Windows "DPI scaling" forces the
window to be scaled.

Also, include math.h