sqInt ioHasDisplayDepth(sqInt depth)

Parms: depth, integer indicating proposed depth
return: true or false, true if the given depth is supported, false otherwise
From: Interpreter
Why:
To find out what the system supports, really we want to know if we can make a 32 bit or 16bit form

Responsibility:
Work with the window system to indicate what depth is supported.
Windows returns negative numbers for LSB based display systems.

MacIntosh
os-9/OSXCarbon
The carbon VM returns true for 1,2,4,8,16,32 bits
Earlier versions of the carbon VM would only return true for 8,16,32 bits

Cocoa:
TBD

iPhone
32 bits only

Unix
16, 32 is supported, 1,2,4,8 could be supported

Windows
1,4,8,16,32 for MSB
LSB returns -8, -16, -32

BUGS
returning negative values for LSB based display systems is not supported on most platforms.