* A command to query the paths referenced by an fstate expression.

* Use a temporary directory for build actions.

src/util.cc

@@ -66,6 +66,18 @@ string baseNameOf(string path)
 }
 
 
+bool pathExists(const string & path)
+{
+    int res;
+    struct stat st;
+    res = stat(path.c_str(), &st);
+    if (!res) return true;
+    if (errno != ENOENT)
+        throw SysError(format("getting status of %1%") % path);
+    return false;
+}
+
+
 void deletePath(string path)
 {
     struct stat st;