It turns out that vfork was completely broken. That was why it

wouldn't run on my little arm7tdmi/uClinux boards, since without
vfork working, nothing works on uClinux.  It took me forever to
find this, since other problems were hiding this one.  Big, huge,
sigh of relief.
 -Erik

libc/sysdeps/linux/arm/Makefile

@@ -35,10 +35,10 @@ endif
 
 CRT0_OBJ=$(patsubst %.S,%.o, $(CRT0))
 
-SSRC=longjmp.S setjmp.S
+SSRC=longjmp.S setjmp.S vfork.S
 SOBJS=$(patsubst %.S,%.o, $(SSRC))
 
-CSRC=fork.c vfork.c
+CSRC=fork.c ptrace.c
 COBJS=$(patsubst %.c,%.o, $(CSRC))
 
 OBJS=$(SOBJS) $(MOBJ) $(COBJS)

libc/sysdeps/linux/arm/vfork.S

@@ -0,0 +1,73 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * fork for uClibc
+ *
+ * Copyright (C) 2000 by Lineo, inc.  Written by Erik Andersen
+ * <andersen@lineo.com>, <andersee@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program 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 Library General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/errno.h>
+#include <asm/unistd.h>
+
+
+.global errno;
+
+
+.text
+.global vfork;
+.type vfork,%function
+.align 4;                                                               \
+
+
+
+vfork:
+
+#ifdef __SYS_vfork
+		swi		__NR_vfork
+		cmn		r0, #4096
+		movcc	pc, lr
+
+		/* Check if vfork even exists.  */
+		ldr     r1, =-ENOSYS
+		teq     r0, r1
+		bne     __syscall_error
+#endif
+
+		/* If we don't have vfork, use fork.  */
+		swi     __NR_fork
+		cmn     r0, #4096
+
+		/* Syscal worked.  Return to child/parent */
+		movcc   pc, lr
+
+__syscall_error:
+
+		/* Looks like the syscall choked -- set errno */
+		ldr  r3, .L4
+		/* Calculate the - of the syscall result, in case we need it */
+		rsb  r2, r0, $0
+
+		/* errno = -result */
+		str  r2, [r9,r3]
+
+		/* return -1 */
+		mvn  r0, $0
+		mov  pc, lr
+
+.L4:  .word errno
+