Correct FIXMEs in libfetchers

src/libutil/hash.hh

@@ -43,7 +43,7 @@ struct Hash
     // hash type must be part of string
     Hash(std::string_view s);
 
-    Hash fromSRI(std::string_view original);
+    static Hash fromSRI(std::string_view original);
 
 private:
     // type must be provided, s must not include <type> prefix

src/libutil/util.cc

@@ -1,5 +1,6 @@
 #include "lazy.hh"
 #include "util.hh"
+#include "hash.hh"
 #include "affinity.hh"
 #include "sync.hh"
 #include "finally.hh"