Change function signature passed to clone

I see the following compile error with an old bfin-uclinux gcc to
build GDBserver,

 cc1: warnings being treated as errors
 gdb/gdbserver/../nat/linux-ptrace.c: In function 'linux_fork_to_function':
 gdb/gdbserver/../nat/linux-ptrace.c:283: error: passing argument 1 of 'clone' from incompatible pointer type

in glibc, clone's prototype is like this, and in uClibc, it is the same,

       int clone(int (*fn)(void *), void *child_stack,
                 int flags, void *arg, ...
                 /* pid_t *ptid, struct user_desc *tls, pid_t *ctid */ );

so this patch changes function signature from 'void (*function) (gdb_byte *)'
to 'int (*function) (void *)'.

Note that I find Pedro advised to change argument type from 'void *'
to 'gdb_byte *' during the patch review
https://sourceware.org/ml/gdb-patches/2013-08/msg00611.html  however,
I think fix compile error can justify the change back to 'void *'.

gdb:

2016-01-12  Yao Qi  <yao.qi@linaro.org>

	* nat/linux-ptrace.c (linux_fork_to_function): Change type
	of argument 'function'.
	(linux_grandchild_function): Change return type to 'int'.
	Change child_stack's type to 'void *'.
	(linux_child_function): Likewise.

1 files changed, 5 insertions, 5 deletions

diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index f25abcf..31757ee 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -261,7 +261,7 @@ linux_ptrace_test_ret_to_nx (void)
    FUNCTION).  For MMU targets, CHILD_STACK is ignored.  */
 
 static int
-linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *))
+linux_fork_to_function (gdb_byte *child_stack, int (*function) (void *))
 {
   int child_pid;
 
@@ -298,8 +298,8 @@ linux_fork_to_function (gdb_byte *child_stack, void (*function) (gdb_byte *))
 /* A helper function for linux_check_ptrace_features, called after
    the child forks a grandchild.  */
 
-static void
-linux_grandchild_function (gdb_byte *child_stack)
+static int
+linux_grandchild_function (void *child_stack)
 {
   /* Free any allocated stack.  */
   xfree (child_stack);
@@ -313,8 +313,8 @@ linux_grandchild_function (gdb_byte *child_stack)
    the parent process forks a child.  The child allows itself to
    be traced by its parent.  */
 
-static void
-linux_child_function (gdb_byte *child_stack)
+static int
+linux_child_function (void *child_stack)
 {
   ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0);
   kill (getpid (), SIGSTOP);