* sysdeps/unix/sysv/linux/i386/ucontext_i.h: File removed.

* sysdeps/unix/sysv/linux/i386/ucontext_i.h: File removed.

	* sysdeps/unix/sysv/linux/i386/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/s390/s390-32/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/s390/s390-64/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/s390/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/sh/sh3/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/sh/sh3/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/sh/sh4/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/sh/sh4/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.h: File removed.
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym: New file.
	* sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = stdlib]:
	(gen-as-const-headers): Add it.
	* sysdeps/unix/sysv/linux/powerpc/Makefile: Likewise.
	* sysdeps/unix/sysv/linux/sh/Makefile: Likewise.
	* sysdeps/unix/sysv/linux/s390/Makefile: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/Makefile: Likewise.
	* stdlib/tst-ucontext-off.c: File removed.
	* stdlib/Makefile (tests): Remove it.

	* scripts/gen-as-const.awk: Support generating a test program.
	* Makerules [gen-as-const-headers] (tests): Add test-as-const.
	[gen-as-const-headers] ($(objpfx)test-as-const.c): New target.