code review 5490053: runtime: make more build-friendly

src/pkg/runtime/signal_freebsd_amd64.c

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include "runtime.h"
-#include "defs.h"
-#include "signals.h"
-#include "os.h"
+#include "defs_GOOS_GOARCH.h"
+#include "signals_GOOS.h"
+#include "os_GOOS.h"
 
 extern void runtime·sigtramp(void);
 
 typedef struct sigaction {
         union {
                 void    (*__sa_handler)(int32);
                 void    (*__sa_sigaction)(int32, Siginfo*, void *);
         } __sigaction_u;                /* signal handler */
         int32   sa_flags;               /* see signal options below */
         int64   sa_mask;                /* signal mask to apply */
@@ skipping 173 matching lines @@
         }
         m->profilehz = hz;
 }
 
 void
 os·sigpipe(void)
 {
         sigaction(SIGPIPE, SIG_DFL, false);
         runtime·raisesigpipe();
 }