make sys/procfs.h mostly work on most archs

these structures are purely for use by trace/debug tools and tools
working with core files. the definition of fpregset_t, which was
previously here, has been removed because it was wrong; fpregset_t
should be the type used in mcontext_t, not the type used in
ptrace/core stuff.

arch/powerpc/bits/user.h

@@ -12,3 +12,14 @@ struct user {
 	unsigned long magic;
 	char u_comm[32];
 };
+
+#define ELF_NGREG 48
+#define ELF_NFPREG 33
+#define ELF_NVRREG 33
+typedef unsigned long elf_greg_t, elf_gregset_t[ELF_NGREG];
+typedef double elf_fpreg_t, elf_fpregset_t[ELF_NFPREG];
+typedef struct { unsigned u[4]; }
+#ifdef __GNUC__
+__attribute__((__aligned__(16)))
+#endif
+	elf_vrreg_t, elf_vrregset_t[ELF_NVRREG];