bsd-user: Include host-os.h from main

Include host-os.h from main.c to pick up the default OS to emulate.  Set
that default in main().

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/bsd-user/main.c b/bsd-user/main.c
index e06cc7b..607fdd8 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -41,6 +41,8 @@
 #include "exec/log.h"
 #include "trace/control.h"
 
+#include "host-os.h"
+
 int singlestep;
 unsigned long mmap_min_addr;
 uintptr_t guest_base;
@@ -352,7 +354,7 @@
     const char *gdbstub = NULL;
     char **target_environ, **wrk;
     envlist_t *envlist = NULL;
-    bsd_type = target_openbsd;
+    bsd_type = HOST_DEFAULT_BSD_TYPE;
 
     if (argc <= 1) {
         usage();