* sysdeps/unix/make-syscalls.sh: Handle new arg signature

	* sysdeps/unix/make-syscalls.sh: Handle new arg signature
	keyletters F, I, S, W.  Remove unused keyletter V.  Surround
	signature argnames with angle-brackets for use as word delimiters,
	and to induce syntax errors for any args not handled.  Split
	multi-echo echoes and comment each stage.
	* sysdeps/unix/common/syscalls.list: Refine & correct signatures.
	* sysdeps/unix/inet/syscalls.list: Likewise.
	* sysdeps/unix/mman/syscalls.list: Likewise.
	* sysdeps/unix/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/ia64/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/mips/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/syscalls.list: Likewise.
	* sysdeps/unix/sysv/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/syscalls.list