runtime: freebsd, netbsd build fixes after reorg

R=golang-dev
CC=golang-dev
https://golang.org/cl/7826044

src/pkg/runtime/os_netbsd.c

@@ -30,6 +30,7 @@ extern void runtime·lwp_mcontext_init(void *mc, void *stack, M *mp, G *gp, void
 extern int32 runtime·lwp_park(Timespec *abstime, int32 unpark, void *hint, void *unparkhint);
 extern int32 runtime·lwp_unpark(int32 lwp, void *hint);
 extern int32 runtime·lwp_self(void);
+extern void runtime·lwp_tramp(void);
 
 // From NetBSD's <sys/sysctl.h>
 #define	CTL_HW	6

src/pkg/runtime/signal_freebsd_386.h

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#define SIG_REGS(ctxt) (*((Ucontext*)(ctxt))->uc_mcontext)
+#define SIG_REGS(ctxt) (((Ucontext*)(ctxt))->uc_mcontext)
 
 #define SIG_EAX(info, ctxt) (SIG_REGS(ctxt).mc_eax)
 #define SIG_EBX(info, ctxt) (SIG_REGS(ctxt).mc_ebx)

src/pkg/runtime/signal_freebsd_amd64.h

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#define SIG_REGS(ctxt) (*((Ucontext*)(ctxt))->uc_mcontext)
+#define SIG_REGS(ctxt) (((Ucontext*)(ctxt))->uc_mcontext)
 
 #define SIG_RAX(info, ctxt) (SIG_REGS(ctxt).mc_rax)
 #define SIG_RBX(info, ctxt) (SIG_REGS(ctxt).mc_rbx)

src/pkg/runtime/signal_freebsd_arm.h

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#define SIG_REGS(ctxt) (*((Sigcontext*)&((Ucontext*)(ctxt))->uc_mcontext))
+#define SIG_REGS(ctxt) (((Sigcontext*)&((Ucontext*)(ctxt))->uc_mcontext))
 
 #define SIG_R0(info, ctxt) (SIG_REGS(ctxt).__gregs[0])
 #define SIG_R1(info, ctxt) (SIG_REGS(ctxt).__gregs[1])