Add an initial clone from glibc. Needs fixing.

libc/sysdeps/linux/arm/clone.S

@@ -0,0 +1,62 @@
+/* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Pat Beirne <patb@corelcomputer.com>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* clone() is even more special than fork() as it mucks with stacks
+   and invokes a function in the right context after its all over.  */
+
+#include <sysdep.h>
+#define _ERRNO_H	1
+#include <bits/errno.h>
+
+/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
+
+        .text
+ENTRY(__clone)
+	@ sanity check args
+	cmp	r0, #0
+	cmpne	r1, #0
+	moveq	r0, #-EINVAL
+	beq	PLTJMP(syscall_error)
+
+	@ insert the args onto the new stack
+	sub	r1, r1, #8
+	str	r3, [r1, #4]
+	@ save the function pointer as the 0th element
+	str	r0, [r1]
+
+	@ do the system call
+	@ get flags
+	mov	r0, r2
+	@ new sp is already in r1
+	swi	SYS_ify(clone)
+	movs	a1, a1
+	blt	PLTJMP(C_SYMBOL_NAME(__syscall_error))
+	RETINSTR(movne, pc, lr)
+
+	@ pick the function arg and call address off the stack and execute
+	ldr	r0, [sp, #4]
+	mov	lr, pc
+	ldr 	pc, [sp]
+
+	@ and we are done, passing the return value through r0
+	b	PLTJMP(_exit)
+
+PSEUDO_END (__clone)
+
+weak_alias (__clone, clone)