+static char depfile_path[PATH_MAX];
+static size_t depfile_prefix_len;
+
+/* touch depfile for symbol 'name' */
+static int conf_touch_dep(const char *name)
+{
+ int fd, ret;
+ const char *s;
+ char *d, c;
+
+ /* check overflow: prefix + name + ".h" + '\0' must fit in buffer. */
+ if (depfile_prefix_len + strlen(name) + 3 > sizeof(depfile_path))
+ return -1;
+
+ d = depfile_path + depfile_prefix_len;
+ s = name;
+
+ while ((c = *s++))
+ *d++ = (c == '_') ? '/' : tolower(c);
+ strcpy(d, ".h");
+
+ /* Assume directory path already exists. */
+ fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+ if (fd == -1) {
+ if (errno != ENOENT)
+ return -1;
+
+ ret = make_parent_dir(depfile_path);
+ if (ret)
+ return ret;
+
+ /* Try it again. */
+ fd = open(depfile_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+ if (fd == -1)
+ return -1;
+ }
+ close(fd);
+
+ return 0;
+}
+