Use MBR by default on BIOS systems. An increasing number of motherboards

assume that GPT means UEFI boot, resulting in the installation of
uninstallable systems. This needs a little more work before MFC, in
particular based on disk size (> 2 TB + BIOS + MBR is not workable). That
will come soon.

usr.sbin/bsdinstall/partedit/partedit_x86.c

@@ -51,7 +51,10 @@ x86_bootmethod(void)
 const char *
 default_scheme(void)
 {
-	return ("GPT");
+	if (strcmp(x86_bootmethod(), "UEFI") == 0)
+		return ("GPT");
+	else
+		return ("MBR");
 }
 
 int