Implement stack protection support

this adds kernel & libroot stack protector hooks. it uses /dev/random in userspace.
A configure option --enable-stack-protector is added to activate -fstack-protector
on selected system components (ATM apps, kits, servers).

Change-Id: If3a2920ba9aa0a85eaff4ba6778947f8c76ade31
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3895
Reviewed-by: Adrien Destugues <[email protected]>

headers/private/kernel/stack_protector.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2021, Jérôme Duval, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _KERNEL_STACK_PROTECTOR_H
+#define _KERNEL_STACK_PROTECTOR_H
+
+
+void stack_protector_init();
+
+
+#endif	/* _KERNEL_STACK_PROTECTOR_H */

headers/private/libroot/libroot_private.h

@@ -55,6 +55,7 @@ void __reinit_pwd_backend_after_fork(void);
 int32 __arch_get_stack_trace(addr_t* returnAddresses, int32 maxCount,
 	int32 skipFrames, addr_t stackBase, addr_t stackEnd);
 
+void __init_stack_protector(void);
 void __set_stack_protection(void);