Fix use of LOAD= with WantSystemLib()...

third_party/libjpeg/libjpeg.scons

 # Copyright 2008, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #    * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # TODO(keunwoo): Use better cross-platform abstraction; see chrome/SConstruct
 Import('env')
 
 env = env.Clone()
 
+if env.WantSystemLib('libjpeg'):
+    Return()
+
 env.Prepend(
     CPPPATH = [
         '$CHROME_SRC_DIR',
     ],
 )
 
 if env['PLATFORM'] == 'win32':
   env.Append(
       CCFLAGS = [
           '/TC',
@@ skipping 45 matching lines @@
     'jidctfst.c',
     'jidctint.c',
     'jmemmgr.c',
     'jmemnobs.c',
     'jquant1.c',
     'jquant2.c',
     'jutils.c',
 ]
 
 env.ChromeStaticLibrary('libjpeg', input_files)