[dev.cc] runtime: convert defs_$GOOS_$GOARCH.h to Go

The conversion was done with an automated tool and then
modified only as necessary to make it compile and run.

In a few cases, defs_$GOOS_$GOARCH.go already existed,
so the target here is defs1_$GOOS_$GOARCH.go.

[This CL is part of the removal of C code from package runtime.
See golang.org/s/dev.cc for an overview.]

LGTM=r
R=r
CC=austin, dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/171490043
diff --git a/src/runtime/defs_openbsd_386.go b/src/runtime/defs_openbsd_386.go
new file mode 100644
index 0000000..a6194a4b
--- /dev/null
+++ b/src/runtime/defs_openbsd_386.go
@@ -0,0 +1,158 @@
+// created by cgo -cdefs and then converted to Go
+// cgo -cdefs defs_openbsd.go
+
+package runtime
+
+import "unsafe"
+
+const (
+	_EINTR  = 0x4
+	_EFAULT = 0xe
+
+	_PROT_NONE  = 0x0
+	_PROT_READ  = 0x1
+	_PROT_WRITE = 0x2
+	_PROT_EXEC  = 0x4
+
+	_MAP_ANON    = 0x1000
+	_MAP_PRIVATE = 0x2
+	_MAP_FIXED   = 0x10
+
+	_MADV_FREE = 0x6
+
+	_SA_SIGINFO = 0x40
+	_SA_RESTART = 0x2
+	_SA_ONSTACK = 0x1
+
+	_SIGHUP    = 0x1
+	_SIGINT    = 0x2
+	_SIGQUIT   = 0x3
+	_SIGILL    = 0x4
+	_SIGTRAP   = 0x5
+	_SIGABRT   = 0x6
+	_SIGEMT    = 0x7
+	_SIGFPE    = 0x8
+	_SIGKILL   = 0x9
+	_SIGBUS    = 0xa
+	_SIGSEGV   = 0xb
+	_SIGSYS    = 0xc
+	_SIGPIPE   = 0xd
+	_SIGALRM   = 0xe
+	_SIGTERM   = 0xf
+	_SIGURG    = 0x10
+	_SIGSTOP   = 0x11
+	_SIGTSTP   = 0x12
+	_SIGCONT   = 0x13
+	_SIGCHLD   = 0x14
+	_SIGTTIN   = 0x15
+	_SIGTTOU   = 0x16
+	_SIGIO     = 0x17
+	_SIGXCPU   = 0x18
+	_SIGXFSZ   = 0x19
+	_SIGVTALRM = 0x1a
+	_SIGPROF   = 0x1b
+	_SIGWINCH  = 0x1c
+	_SIGINFO   = 0x1d
+	_SIGUSR1   = 0x1e
+	_SIGUSR2   = 0x1f
+
+	_FPE_INTDIV = 0x1
+	_FPE_INTOVF = 0x2
+	_FPE_FLTDIV = 0x3
+	_FPE_FLTOVF = 0x4
+	_FPE_FLTUND = 0x5
+	_FPE_FLTRES = 0x6
+	_FPE_FLTINV = 0x7
+	_FPE_FLTSUB = 0x8
+
+	_BUS_ADRALN = 0x1
+	_BUS_ADRERR = 0x2
+	_BUS_OBJERR = 0x3
+
+	_SEGV_MAPERR = 0x1
+	_SEGV_ACCERR = 0x2
+
+	_ITIMER_REAL    = 0x0
+	_ITIMER_VIRTUAL = 0x1
+	_ITIMER_PROF    = 0x2
+
+	_EV_ADD       = 0x1
+	_EV_DELETE    = 0x2
+	_EV_CLEAR     = 0x20
+	_EV_ERROR     = 0x4000
+	_EVFILT_READ  = -0x1
+	_EVFILT_WRITE = -0x2
+)
+
+type tforkt struct {
+	tf_tcb   *byte
+	tf_tid   *int32
+	tf_stack *byte
+}
+
+type sigaltstackt struct {
+	ss_sp    *byte
+	ss_size  uint32
+	ss_flags int32
+}
+
+type sigcontext struct {
+	sc_gs       int32
+	sc_fs       int32
+	sc_es       int32
+	sc_ds       int32
+	sc_edi      int32
+	sc_esi      int32
+	sc_ebp      int32
+	sc_ebx      int32
+	sc_edx      int32
+	sc_ecx      int32
+	sc_eax      int32
+	sc_eip      int32
+	sc_cs       int32
+	sc_eflags   int32
+	sc_esp      int32
+	sc_ss       int32
+	__sc_unused int32
+	sc_mask     int32
+	sc_trapno   int32
+	sc_err      int32
+	sc_fpstate  unsafe.Pointer
+}
+
+type siginfo struct {
+	si_signo int32
+	si_code  int32
+	si_errno int32
+	_data    [116]byte
+}
+
+type stackt struct {
+	ss_sp    *byte
+	ss_size  uint32
+	ss_flags int32
+}
+
+type timespec struct {
+	tv_sec  int64
+	tv_nsec int32
+}
+
+type timeval struct {
+	tv_sec  int64
+	tv_usec int32
+}
+
+type itimerval struct {
+	it_interval timeval
+	it_value    timeval
+}
+
+type keventt struct {
+	ident  uint32
+	filter int16
+	flags  uint16
+	fflags uint32
+	data   int64
+	udata  *byte
+}