Configure : automatically detect the need to enable use_32bit

[mmadia]

Configure should perform a simple check and conditionally enable the use_32bit flag.

Currently, Haiku does not support 64bit mode. Until it does, this sample code will help to unify the configure command across build platforms.

This is especially useful for creating a build script that can be run on any platform. Specifically, for ​Bitten, which I am currently working on.

# check for a 64bit platform
platform_machine=`uname  -m`
case "${platform_machine}" in
	x86_64)	use_32bit=1 ;;
	*)	echo Assuming 32-bit machine: "$platform_machine"
		use_32bit=0 ;;
esac

[mmadia]

This should detect FreeBSD 64 and exit

line 337

FreeBSD) buildPlatform=freebsd
	 if [ "$use_32bit" = 1 ]; then
		echo Unsupported platform: FreeBSD `uname -m`
		exit 1 ;;
	 fi

Later, I'll create a patch for all of this and try to find someone willing to test.

[mmadia]

preliminary patch

[bonefish]

Applied in hrev29314. Thanks!