[GN]: Support for loadable modules

build/toolchain/mac/BUILD.gn

 # 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.
 
 # TODO(brettw) Use "gcc_toolchain.gni" like the Linux toolchains. This requires
 # some enhancements since the commands on Mac are slightly different than on
 # Linux.
 
 import("../goma.gni")
 import("//build/config/ios/ios_sdk.gni")
@@ skipping 100 matching lines @@
       ]
       default_output_extension = ".a"
       output_prefix = "lib"
     }
 
     tool("solink") {
       dylib = "{{root_out_dir}}/{{target_output_name}}{{output_extension}}"  # eg "./libfoo.dylib"
       rspfile = dylib + ".rsp"
 
       # These variables are not built into GN but are helpers that implement
-      # (1) linking to produce a .so, (2) extracting the symbols from that file
-      # to a temporary file, (3) if the temporary file has differences from the
-      # existing .TOC file, overwrite it, otherwise, don't change it.
+      # (1) linking to produce a .dylib, (2) extracting the symbols from that
+      # file to a temporary file, (3) if the temporary file has differences from
+      # the existing .TOC file, overwrite it, otherwise, don't change it.
       #
       # As a special case, if the library reexports symbols from other dynamic
       # libraries, we always update the .TOC and skip the temporary file and
       # diffing steps, since that library always needs to be re-linked.
       tocname = dylib + ".TOC"
       temporary_tocname = dylib + ".tmp"
 
       does_reexport_command = "[ ! -e $dylib -o ! -e $tocname ] || otool -l $dylib | grep -q LC_REEXPORT_DYLIB"
 
       link_command = "$ld -shared {{ldflags}} -o $dylib -Wl,-filelist,$rspfile"
@@ skipping 116 matching lines @@
 }
 
 mac_toolchain("x64") {
   toolchain_cpu = "x64"
   toolchain_os = "mac"
   cc = "${goma_prefix}/gcc"
   cxx = "${goma_prefix}/g++"
   ld = cxx
   is_clang = false
 }