Special-case paths that appear in libs by not prefixing them with -l.

tools/gn/config_values_generator.cc

Index: tools/gn/config_values_generator.cc
diff --git a/tools/gn/config_values_generator.cc b/tools/gn/config_values_generator.cc
index ca87d6363aea35c7df189f62ebb8ae1c0f012764..3cc8235face1472d3c858b8f82c736e5c45d12f8 100644
--- a/tools/gn/config_values_generator.cc
+++ b/tools/gn/config_values_generator.cc
@@ -24,9 +24,7 @@ void GetStringList(
   if (!value)
     return;  // No value, empty input and succeed.
 
-  std::vector<std::string> result;
-  ExtractListOfStringValues(*value, &result, err);
-  (config_values->*accessor)().swap(result);
+  ExtractListOfStringValues(*value, &(config_values->*accessor)(), err);
 }
 
 void GetDirList(
@@ -79,11 +77,17 @@ void ConfigValuesGenerator::Run() {
   FILL_DIR_CONFIG_VALUE(   include_dirs)
   FILL_STRING_CONFIG_VALUE(ldflags)
   FILL_DIR_CONFIG_VALUE(   lib_dirs)
-  FILL_STRING_CONFIG_VALUE(libs)
 
 #undef FILL_STRING_CONFIG_VALUE
 #undef FILL_DIR_CONFIG_VALUE
 
+  // Libs
+  const Value* libs_value = scope_->GetValue("libs", true);
+  if (libs_value) {
+    ExtractListOfLibs(scope_->settings()->build_settings(), *libs_value,
+                      input_dir_, &config_values_->libs(), err_);
+  }
+
   // Precompiled headers.
   const Value* precompiled_header_value =
       scope_->GetValue(variables::kPrecompiledHeader, true);