* sysdeps/unix/sysv/linux/i386/sigaction.c: New file.
* sysdeps/unix/sysv/linux/i386/xstat.S: Don't use JUMPTARGET macro
on syscall_error. For PIC, it is a local label;
for non-PIC, JUMPTARGET expands to the unadorned name anyway.
* sysdeps/unix/sysv/linux/i386/xmknod.S: Likewise.
* sysdeps/unix/sysv/linux/i386/syscall.S: Likewise.
* sysdeps/unix/sysv/linux/i386/socket.S: Likewise.
* sysdeps/unix/sysv/linux/i386/sbrk.S: Likewise.
* sysdeps/unix/sysv/linux/i386/mmap.S: Likewise.
* sysdeps/unix/sysv/linux/i386/brk.S: Likewise.