Revert rev. 226893: subr_syscall.c is being included from C files and

on amd64 with FREEBSD32 enabled, this means that systrace_probe_func
gets defined twice.

sys/amd64/amd64/trap.c

@@ -103,6 +103,13 @@ dtrace_trap_func_t	dtrace_trap_func;
 
 dtrace_doubletrap_func_t	dtrace_doubletrap_func;
 
+/*
+ * This is a hook which is initialised by the systrace module
+ * when it is loaded. This keeps the DTrace syscall provider
+ * implementation opaque. 
+ */
+systrace_probe_func_t	systrace_probe_func;
+
 /*
  * These hooks are necessary for the pid, usdt and fasttrap providers.
  */

sys/i386/i386/trap.c

@@ -112,6 +112,13 @@ dtrace_trap_func_t	dtrace_trap_func;
 
 dtrace_doubletrap_func_t	dtrace_doubletrap_func;
 
+/*
+ * This is a hook which is initialised by the systrace module
+ * when it is loaded. This keeps the DTrace syscall provider
+ * implementation opaque. 
+ */
+systrace_probe_func_t	systrace_probe_func;
+
 /*
  * These hooks are necessary for the pid, usdt and fasttrap providers.
  */

sys/kern/subr_syscall.c

@@ -52,15 +52,6 @@ __FBSDID("$FreeBSD$");
 #endif
 #include <security/audit/audit.h>
 
-#ifdef KDTRACE_HOOKS
-/*
- * This is a hook which is initialised by the systrace module
- * when it is loaded. This keeps the DTrace syscall provider
- * implementation opaque.
- */
-systrace_probe_func_t systrace_probe_func;
-#endif
-
 static inline int
 syscallenter(struct thread *td, struct syscall_args *sa)
 {