Support Mac frameworks in GN.

tools/gn/function_toolchain.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/err.h"
 #include "tools/gn/functions.h"
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/settings.h"
@@ skipping 133 matching lines @@
     "  prevent GN from doing variable expansion.\n"
     "\n"
     "    command, depfile, deps, description, pool, restat, rspfile,\n"
     "    rspfile_content\n"
     "\n"
     "  Additionally, lib_prefix and lib_dir_prefix may be used for the link\n"
     "  tools. These strings will be prepended to the libraries and library\n"
     "  search directories, respectively, because linkers differ on how to\n"
     "  specify them.\n"
     "\n"
+    "  Note: On Mac libraries with names ending in \".framework\" will be\n"
+    "  added to the link like with a \"-framework\" switch and the lib prefix\n"
+    "  will be ignored.\n"
+    "\n"
     "Example:\n"
     "  toolchain(\"my_toolchain\") {\n"
     "    # Put these at the top to apply to all tools below.\n"
     "    lib_prefix = \"-l\"\n"
     "    lib_dir_prefix = \"-L\"\n"
     "\n"
     "    tool(\"cc\") {\n"
     "      command = \"gcc \\$in -o \\$out\"\n"
     "      description = \"GCC \\$in\"\n"
     "    }\n"
@@ skipping 124 matching lines @@
     return Value();
 
   Scope::KeyValueMap values;
   block_scope.GetCurrentScopeValues(&values);
   toolchain->args() = values;
 
   return Value();
 }
 
 }  // namespace functions