-#include "cache.h"
+#include "builtin.h"
 #include "commit.h"
 #include "tag.h"
 #include "merge-recursive.h"
+#include "xdiff-interface.h"
 
 static const char builtin_merge_recursive_usage[] =
        "git %s <base>... -- <head> <remote> ...";
                if (!prefixcmp(arg, "--")) {
                        if (!arg[2])
                                break;
-                       if (!strcmp(arg+2, "ours"))
-                               o.recursive_variant = MERGE_RECURSIVE_OURS;
-                       else if (!strcmp(arg+2, "theirs"))
-                               o.recursive_variant = MERGE_RECURSIVE_THEIRS;
-                       else if (!strcmp(arg+2, "subtree"))
-                               o.subtree_shift = "";
-                       else if (!prefixcmp(arg+2, "subtree="))
-                               o.subtree_shift = arg + 10;
-                       else if (!strcmp(arg+2, "renormalize"))
-                               o.renormalize = 1;
-                       else if (!strcmp(arg+2, "no-renormalize"))
-                               o.renormalize = 0;
-                       else
+                       if (parse_merge_opt(&o, arg + 2))
                                die("Unknown option %s", arg);
                        continue;
                }