diff --git a/configure.c b/configure.c
index b01b351..574b75f 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>
@@ -185,18 +186,34 @@ cmd_stdout(char *cmd)
     FILE *f;
     char *line = NULL;
     size_t size;
+    int result;
     if (!cmd)
     {
-        return NULL;
+        goto failure;
     }
     if (!(f = popen(cmd, "r")))
     {
-        return NULL;
+        goto failure;
     }
 
     getline(&line, &size, f);
-    pclose(f);
+    result = pclose(f);
+
+    if (result < 0)
+    {
+        perror("pclose(3)");
+        goto failure;
+    }
+    else if (result)
+    {
+        fprintf(stderr, "command exited with status %d: %s\n", result, cmd);
+        goto failure;
+    }
     return line;
+
+failure:
+    free(line);
+    return NULL;
 }
 static int
 exec_code(char *program, char *argv[])
@@ -293,7 +310,8 @@ collect_sources(char *dir, bool head, char *ext)
     while ((ent = readdir(handle)))
     {
         char *name = ent->d_name;
-        if (*name == '.') continue;
+
+        if (!strcmp(name, ".") || !strcmp(name, "..")) continue;
 
         if (strlen(name) > strlen(ext) && 
             !strcmp(name + strlen(name) - strlen(ext), ext))
@@ -305,22 +323,29 @@ 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);
         }
@@ -417,10 +442,13 @@ main_build(int argc, char *argv[])
     int opt;
     str_array_t *sources, *images, *utils, *aya;
 
-    if (strchr(repo, '\n'))
+    if (repo)
     {
-        *(strchr(repo,  '\n')) = '\0';
+        char *lf = strchr(repo, '\n');
+        *lf = '\0';
     }
+    else
+        repo = strdup("N/A");
 
     while ((opt = getopt(argc, argv, "sl")) != -1)
     {
@@ -555,6 +583,7 @@ main_build(int argc, char *argv[])
                 fprintf(makefile, " -static");
             }
             fprintf(makefile, " $<");
+            fprintf(makefile, " -I $(CYTO_INC)");
             fprintf(makefile, " -L $(CYTO_LIB)");
             if (with_static)
             {