diff --git a/libyasm/genmodule.c b/libyasm/genmodule.c
index 867d93a..027e2fe 100644
--- a/libyasm/genmodule.c
+++ b/libyasm/genmodule.c
@@ -58,9 +58,14 @@ main(int argc, char *argv[])
     include *inc;
     int isam = 0;
     int linecont = 0;
-
-    if (argc != 3) {
-        fprintf(stderr, "Usage: %s <module.in> <Makefile[.am]>\n", argv[0]);
+    char *outfile;
+
+    if (argc == 3) {
+        outfile = OUTPUT;
+    } else if (argc == 4) {
+        outfile = argv[3];
+    } else {
+        fprintf(stderr, "Usage: %s <module.in> <Makefile[.am]> [<outfile>]\n", argv[0]);
         return EXIT_FAILURE;
     }
 
@@ -167,10 +172,10 @@ keepgoing:
         fclose(in);
     }
 
-    out = fopen(OUTPUT, "wt");
+    out = fopen(outfile, "wt");
 
     if (!out) {
-        fprintf(stderr, "Could not open `%s'.\n", OUTPUT);
+        fprintf(stderr, "Could not open `%s'.\n", outfile);
         return EXIT_FAILURE;
     }
 
@@ -181,7 +186,7 @@ keepgoing:
     if (!in) {
         fprintf(stderr, "Could not open `%s'.\n", argv[1]);
         fclose(out);
-        remove(OUTPUT);
+        remove(outfile);
         return EXIT_FAILURE;
     }