Rename sys/ucontext.h to bits/ucontext.h.zack/no-nested-includes

sys/ucontext.h is effectively a bits header.  Its contents are
extremely system-specific, and it’s strongly associated with a
specific public header (ucontext.h) that provides a superset of its
definitions, but there are other public headers that also require some
of its definitions.  This patch therefore moves it into the bits/
namespace and adjusts all the headers that refer to it.  In case there
are external users, a stub is added that includes ucontext.h.

Most of the fallout changes are trivial, but aarch64, ia64 and riscv
need a little more work.  aarch64 sys/ucontext.h (now bits/ucontext.h)
was including sys/procfs.h for the definition of elf_greg_t etc;
the simplest fix is to have it include bits/procfs.h instead (and then
that needs to include sys/user.h for user_regs_struct).  This is not
ideal but fixing it properly would require disentangling all of the
debugger interface headers which is more than I’m up for at the moment.

ia64 bits/ptrace.h and bits/procfs.h were both including
bits/sigcontext.h, which is only licensed to be included from
signal.h.  (I’m not sure how this ever worked, or why it broke with
this patch and not some previous one.)  This is fixed by creating
another single-type header, bits/types/__ia64_fpreg.h, which provides
the only thing they need from bits/sigcontext.h.

s/u/s/l/riscv/makecontext.c was defining makecontext with a function
head that didn’t agree with its official prototype (in ucontext.h);
formerly that file did not include ucontext.h, only sys/ucontext.h,
so we were getting away with it, but it’s still wrong.  Making the
function head match the prototype actually simplifies the code.

	* sysdeps/generic/sys/ucontext.h: Move to top level bits/ucontext.h.
	Adjust multiple inclusion guard.
	* sysdeps/arm/sys/ucontext.h: Move to sysdeps/arm/bits/ucontext.h.
	Adjust multiple inclusion guard.
	* sysdeps/i386/sys/ucontext.h: Similarly.
	* sysdeps/m68k/sys/ucontext.h: Similarly.
	* sysdeps/mips/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/alpha/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/arm/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/csky/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/hppa/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/ia64/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/m68k/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/microblaze/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/mips/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/nios2/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/riscv/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/s390/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/sparc/sys/ucontext.h: Similarly.
	* sysdeps/unix/sysv/linux/x86/sys/ucontext.h: Similarly.
	* stdlib/Makefile: Install bits/ucontext.h.

	* stdlib/sys/ucontext.h: New backward compatibility stub header,
	includes ucontext.h.
	* include/sys/ucontext.h: New wrapper.

	* sysdeps/unix/sysv/linux/aarch64/bits/procfs.h: Allow inclusion
	by bits/ucontext.h as well as sys/procfs.h.  Include sys/user.h.
	* sysdeps/unix/sysv/linux/aarch64/bits/ucontext.h: Include
	bits/procfs.h instead of sys/procfs.h.

	* sysdeps/unix/sysv/linux/ia64/bits/types/__ia64_fpreg.h:
	New file, contents factored out of ia64/bits/sigcontext.h and
	ia64/bits/ucontext.h.
	* sysdeps/unix/sysv/linux/ia64/Makefile:
	Install bits/types/__ia64_fpreg.h.  Merge subdir=misc blocks.
	* sysdeps/unix/sysv/linux/ia64/bits/sigcontext.h
	* sysdeps/unix/sysv/linux/ia64/bits/ucontext.h:
	Include bits/types/__ia64_fpreg.h for struct ia64_fpreg.

	* sysdeps/unix/sysv/linux/ia64/bits/procfs.h:
	Include bits/types/__ia64_fpreg.h for struct ia64_fpreg.
	Don’t include bits/sigcontext.h or bits/ucontext.h.
	* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h:
	Don’t include bits/sigcontext.h.

	* sysdeps/unix/sysv/linux/riscv/makecontext.c: Include
	ucontext.h, not sys/ucontext.h. Correct function head to match
	prototype in ucontext.h.  Use va_arg to retrieve all arguments
	past argc.

	* sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c:
	Sort list of includes.

	* signal/signal.h, stdlib/ucontext.h
	* sysdeps/unix/sysv/linux/alpha/bits/procfs-prregset.h
	* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h
	* sysdeps/unix/sysv/linux/riscv/bits/procfs.h
	* sysdeps/unix/sysv/linux/s390/bits/procfs.h:
	Include bits/ucontext.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/aarch64/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
	* sysdeps/unix/sysv/linux/riscv/sigcontextinfo.h:
	Include signal.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/arm/register-dump.h
	* sysdeps/unix/sysv/linux/csky/register-dump.h:
	Include ucontext.h, not sys/ucontext.h.

	* sysdeps/unix/sysv/linux/aarch64/ucontext_i.sym
	* sysdeps/unix/sysv/linux/alpha/ucontext-offsets.sym
	* sysdeps/unix/sysv/linux/arm/ucontext_i.sym
	* sysdeps/unix/sysv/linux/csky/abiv2/ucontext_i.sym
	* sysdeps/unix/sysv/linux/hppa/ucontext_i.sym
	* sysdeps/unix/sysv/linux/i386/ucontext_i.sym
	* sysdeps/unix/sysv/linux/ia64/sigcontext-offsets.sym
	* sysdeps/unix/sysv/linux/m68k/m680x0/ucontext_i.sym
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/ucontext_i.sym
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym
	* sysdeps/unix/sysv/linux/mips/ucontext_i.sym
	* sysdeps/unix/sysv/linux/nios2/ucontext_i.sym
	* sysdeps/unix/sysv/linux/riscv/ucontext_i.sym
	* sysdeps/unix/sysv/linux/s390/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sh/sh3/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sh/sh4/ucontext_i.sym
	* sysdeps/unix/sysv/linux/sparc/sparc32/ucontext_i.sym
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym:
	Include stddef.h and signal.h; don’t include any other headers.

	* scripts/check-obsolete-constructs.py (HEADER_ALLOWED_INCLUDES)
	(SYSDEP_ALLOWED_INCLUDES): Update.

2 files changed, 3 insertions, 5 deletions

diff --git a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h b/sysdeps/unix/sysv/linux/mips/bits/ucontext.h
index 5bbc8a63b9..2f4d9d786b 100644
--- a/sysdeps/unix/sysv/linux/mips/sys/ucontext.h
+++ b/sysdeps/unix/sysv/linux/mips/bits/ucontext.h
@@ -16,8 +16,8 @@
 
 /* Don't rely on this, the interface is currently messed up and may need to
    be broken to be fixed.  */
-#ifndef _SYS_UCONTEXT_H
-#define _SYS_UCONTEXT_H	1
+#ifndef _BITS_UCONTEXT_H
+#define _BITS_UCONTEXT_H	1
 
 #include <features.h>
 
@@ -121,4 +121,4 @@ typedef struct ucontext_t
 
 #undef __ctx
 
-#endif /* sys/ucontext.h */
+#endif /* bits/ucontext.h */
diff --git a/sysdeps/unix/sysv/linux/mips/ucontext_i.sym b/sysdeps/unix/sysv/linux/mips/ucontext_i.sym
index f14b886407..d9692adcba 100644
--- a/sysdeps/unix/sysv/linux/mips/ucontext_i.sym
+++ b/sysdeps/unix/sysv/linux/mips/ucontext_i.sym
@@ -1,7 +1,5 @@
-#include <inttypes.h>
 #include <signal.h>
 #include <stddef.h>
-#include <sys/ucontext.h>
 
 #include <kernel_rt_sigframe.h>