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

tools/gn/value_extractors.cc

Index: tools/gn/value_extractors.cc
diff --git a/tools/gn/value_extractors.cc b/tools/gn/value_extractors.cc
index 365c5342779c841b79e34337ff6cc4a93c7a1add..ec42e66453a2892f9820cef02ed93ddf8a900379 100644
--- a/tools/gn/value_extractors.cc
+++ b/tools/gn/value_extractors.cc
@@ -73,6 +73,27 @@ struct RelativeFileConverter {
   const SourceDir& current_dir;
 };
 
+struct LibFileConverter {
+  LibFileConverter(const BuildSettings* build_settings_in,
+                   const SourceDir& current_dir_in)
+      : build_settings(build_settings_in),
+        current_dir(current_dir_in) {
+  }
+  bool operator()(const Value& v, LibFile* out, Err* err) const {
+    if (!v.VerifyTypeIs(Value::STRING, err))
+      return false;
+    if (v.string_value().find('/') == std::string::npos) {
+      *out = LibFile(v.string_value());
+    } else {
+      *out = LibFile(current_dir.ResolveRelativeFile(
+          v, err, build_settings->root_path_utf8()));
+    }
+    return !err->has_error();
+  }
+  const BuildSettings* build_settings;
+  const SourceDir& current_dir;
+};
+
 struct RelativeDirConverter {
   RelativeDirConverter(const BuildSettings* build_settings_in,
                        const SourceDir& current_dir_in)
@@ -147,6 +168,15 @@ bool ExtractListOfRelativeFiles(const BuildSettings* build_settings,
                             RelativeFileConverter(build_settings, current_dir));
 }
 
+bool ExtractListOfLibs(const BuildSettings* build_settings,
+                       const Value& value,
+                       const SourceDir& current_dir,
+                       std::vector<LibFile>* libs,
+                       Err* err) {
+  return ListValueExtractor(value, libs, err,
+                            LibFileConverter(build_settings, current_dir));
+}
+
 bool ExtractListOfRelativeDirs(const BuildSettings* build_settings,
                                const Value& value,
                                const SourceDir& current_dir,