diff --git a/configure.c b/configure.c
index b0cbee6..6d1f1a7 100644
--- a/configure.c
+++ b/configure.c
@@ -11,6 +11,7 @@
 #include <sys/stat.h>
 #include <stdbool.h>
 #include <dirent.h>
+#include <errno.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <limits.h>
@@ -306,22 +307,29 @@ collect_sources(char *dir, bool head, char *ext)
             free(na);
             continue;
         }
-        if (!strchr(name, '.') && 
-            strcmp(name, "out") &&
-            strcmp(name, "Makefile"))
         {
-            str_array_t *sub;
             char *d1 = string_cat(dir, "/");
             char *d2 = string_cat(d1, name);
             size_t i;
+            struct stat sb;
 
-            sub = collect_sources(d2, false, ext);
-            for (i = 0; i < str_array_len(sub); i++)
+            if (stat(d2, &sb))
             {
-                char *file = str_array_get(sub, i);
-                str_array_add(ret, file);
+                fprintf(stderr, "stat(2) %s: %s\n", d2, strerror(errno));
+                free(d2);
+                free(d1);
             }
-            str_array_free(sub);
+            else if (S_ISDIR(sb.st_mode))
+            {
+                str_array_t *sub = collect_sources(d2, false, ext);
+                for (i = 0; i < str_array_len(sub); i++)
+                {
+                    char *file = str_array_get(sub, i);
+                    str_array_add(ret, file);
+                }
+                str_array_free(sub);
+            }
+
             free(d2);
             free(d1);
         }