Plumb system_libdir variable from GN to pkg-config.py

build/config/linux/pkg-config.py

 # 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.
 
 import json
 import os
 import subprocess
 import sys
 import re
 from optparse import OptionParser
 
 # This script runs pkg-config, optionally filtering out some results, and
 # returns the result.
 #
 # The result will be [ <includes>, <cflags>, <libs>, <lib_dirs>, <ldflags> ]
 # where each member is itself a list of strings.
 #
 # You can filter out matches using "-v <regexp>" where all results from
 # pkgconfig matching the given regular expression will be ignored. You can
 # specify more than one regular expression my specifying "-v" more than once.
 #
 # You can specify a sysroot using "-s <sysroot>" where sysroot is the absolute
 # system path to the sysroot used for compiling. This script will attempt to
 # generate correct paths for the sysroot.
 #
 # When using a sysroot, you must also specify the architecture via
 # "-a <arch>" where arch is either "x86" or "x64".
 #
+# CrOS systemroots place pkgconfig files at <systemroot>/usr/share/pkgconfig
+# and one of <systemroot>/usr/lib/pkgconfig or <systemroot>/usr/lib64/pkgconfig
+# depending on whether the systemroot is for a 32 or 64 bit architecture. They
+# specify the 'lib' or 'lib64' of the pkgconfig path by defining the
+# 'system_libdir' variable in the args.gn file. pkg_config.gni communicates this
+# variable to this script with the "--system_libdir <system_libdir>" flag. If no
+# flag is provided, then pkgconfig files are assumed to come from
+# <systemroot>/usr/lib/pkgconfig.
+#
 # Additionally, you can specify the option --atleast-version. This will skip
 # the normal outputting of a dictionary and instead print true or false,
 # depending on the return value of pkg-config for the given package.
 
 # If this is run on non-Linux platforms, just return nothing and indicate
 # success. This allows us to "kind of emulate" a Linux build from other
 # platforms.
 if sys.platform.find("linux") == -1:
   print "[[],[],[],[],[]]"
   sys.exit(0)
 
 
 def SetConfigPath(options):
   """Set the PKG_CONFIG_PATH environment variable.
   This takes into account any sysroot and architecture specification from the
   options on the given command line."""
 
   sysroot = options.sysroot
   if not sysroot:
     sysroot = ""
 
   # Compute the library path name based on the architecture.
   arch = options.arch
   if sysroot and not arch:
     print "You must specify an architecture via -a if using a sysroot."
     sys.exit(1)
 
-  # In the gyp world this is configurable via the 'system_libdir' variable,
-  # which doesn't seem to have an equivelent in gn yet.
-  # TOOD(sbc): Make this configurable like it is under gyp.
-  libpath = 'lib'
-
   # Add the sysroot path to the environment's PKG_CONFIG_PATH
-  config_path = sysroot + '/usr/' + libpath + '/pkgconfig'
+  config_path = sysroot + '/usr/' + options.system_libdir + '/pkgconfig'
   config_path += ':' + sysroot + '/usr/share/pkgconfig'
   if 'PKG_CONFIG_PATH' in os.environ:
     os.environ['PKG_CONFIG_PATH'] += ':' + config_path
   else:
     os.environ['PKG_CONFIG_PATH'] = config_path
 
 
 def GetPkgConfigPrefixToStrip(args):
   """Returns the prefix from pkg-config where packages are installed.
   This returned prefix is the one that should be stripped from the beginning of
@@ skipping 31 matching lines @@
   else:
     return path
 
 
 parser = OptionParser()
 parser.add_option('-p', action='store', dest='pkg_config', type='string',
                   default='pkg-config')
 parser.add_option('-v', action='append', dest='strip_out', type='string')
 parser.add_option('-s', action='store', dest='sysroot', type='string')
 parser.add_option('-a', action='store', dest='arch', type='string')
+parser.add_option('--system_libdir', action='store', dest='system_libdir',
+                  type='string', default='lib')
 parser.add_option('--atleast-version', action='store',
                   dest='atleast_version', type='string')
 parser.add_option('--libdir', action='store_true', dest='libdir')
 (options, args) = parser.parse_args()
 
 # Make a list of regular expressions to strip out.
 strip_out = []
 if options.strip_out != None:
   for regexp in options.strip_out:
     strip_out.append(re.compile(regexp))
@@ skipping 68 matching lines @@
     # this anyway. Removing it here prevents a bunch of duplicate inclusions on
     # the command line.
     pass
   else:
     cflags.append(flag)
 
 # Output a GN array, the first one is the cflags, the second are the libs. The
 # JSON formatter prints GN compatible lists when everything is a list of
 # strings.
 print json.dumps([includes, cflags, libs, lib_dirs, ldflags])