Fix Ada.Processes.Shell to raise Name_Error when the execution of the shell failed
Use < 0 instead of = -1 for return values of system calls
Fix a bug of mismatched lengths of Ada.Characters.Normalization, again
Insert pragma No_Return for __builtin_unreachable
Fix pragma Assert of Ada.Text_IO.Editing
Use pragma Check instead of pragma Assert
Grammar corrections
Improve Character'Image and 'Width
Use 'Mod to convert from C.unwind.Unwind_Sword to Unwind_Word instead of Ada.Unchecked_Conversion
Use System'To_Address
Merge commit 'f727025' into gcc-4.8

Conflicts:
	source/machine-w64-mingw32/i386/s-unwmap.adb
	source/machine-w64-mingw32/x86_64/s-unwmap.adb

Modifications:
	source/zcx/s-untrse.adb
Use System.Storage_Elements for address arithmetic
Merge commit 'f0833c1' into gcc-4.8

Conflicts:
	source/machine-apple-darwin/s-natsta.adb
	source/machine-pc-freebsd/s-natsta.adb
	source/machine-pc-linux-gnu/s-natsta.adb