Make symbol resolution failures log under rust_log::ERR flag as well.

Author: graydon

src/rt/rust_crate_cache.cpp

@@ -120,7 +120,8 @@ rust_crate_cache::rust_sym::rust_sym(rust_dom *dom,
     if (found_leaf) {
         dom->log(rust_log::CACHE, "resolved symbol to 0x%"  PRIxPTR, val);
     } else {
-        dom->log(rust_log::CACHE, "failed to resolve symbol");
+        dom->log(rust_log::CACHE | rust_log::ERR,
+                 "failed to resolve symbol");
     }
 }
 

src/rt/rust_upcall.cpp

@@ -535,8 +535,8 @@ upcall_require_c_sym(rust_task *task,
         task->log(rust_log::UPCALL | rust_log::CACHE,
                   "found-or-cached addr: 0x%" PRIxPTR, addr);
     } else {
-        task->log(rust_log::UPCALL | rust_log::CACHE,
-                  "failed to resolve symbol");
+        task->log(rust_log::UPCALL | rust_log::CACHE | rust_log::ERR,
+                  "failed to resolve symbol %s in %s", symbol, library);
         task->fail(6);
     }
     return addr;