Auto merge of #599 - xd009642:master, r=alexcrichton

Adding missing structs from linux/user.h

Adding structs from linux/user.h (or sys/user.h depending on OS version). This adds the linux user_regs_struct and user struct from sys/user.h into libc for x86 and x86_64. Also, bumping the version number.

As an aside, I was wondering if this was also the right place to add the bit offsets for the [EFLAGS register ](https://en.wikibooks.org/wiki/X86_Assembly/X86_Architecture#EFLAGS_Register)? These aren't defined anywhere in the linux system libraries instead the definition seems to just be in the x86 and x86_64 documentation but they are useful for anyone looking to interpret eflags. If libc is the right place for these constants I'd like the opportunity to add them before it's merged in. :)