crypto, exec, path, time: add support for OpenBSD

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4837048

src/pkg/crypto/rand/Makefile

@@ -19,6 +19,9 @@ GOFILES_darwin=\
 GOFILES_linux=\
 	rand_unix.go\
 
+GOFILES_openbsd=\
+	rand_unix.go\
+
 GOFILES_windows=\
 	rand_windows.go\
 

src/pkg/exec/Makefile

@@ -17,6 +17,9 @@ GOFILES_darwin=\
 GOFILES_linux=\
 	lp_unix.go\
 
+GOFILES_openbsd=\
+	lp_unix.go\
+
 GOFILES_windows=\
 	lp_windows.go\
 

src/pkg/path/filepath/Makefile

@@ -18,6 +18,9 @@ GOFILES_darwin=\
 GOFILES_linux=\
 	path_unix.go
 
+GOFILES_openbsd=\
+	path_unix.go
+
 GOFILES_plan9=\
 	path_plan9.go
 

src/pkg/time/Makefile

@@ -27,6 +27,11 @@ GOFILES_linux=\
 	zoneinfo_posix.go\
 	zoneinfo_unix.go\
 
+GOFILES_openbsd=\
+	sys_posix.go\
+	zoneinfo_posix.go\
+	zoneinfo_unix.go\
+
 GOFILES_windows=\
 	sys_posix.go\
 	zoneinfo_windows.go\