Fix examples/signal.adb not to use the unit in ada83
Start to support Windows (mingw-w64)
Merge branch 'master' (gcc-4.7, commit '1b62524') into gcc-4.6

Conflicts:
	source/zcx/s-unrase.adb

Modifications:
	examples/makefile
	source/makefile
	source/sjlj/s-unrase.adb
	source/sjlj/s-unwhan.adb
	source/sjlj/s-unwhan.ads