PNaCl driver: Add libgcc to mixed native/bitcode links

pnacl/driver/pnacl-driver.py

 #!/usr/bin/python
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # IMPORTANT NOTE: If you make local mods to this file, you must run:
 #   %  pnacl/build.sh driver
 # in order for them to take effect in the scons build.  This command
 # updates the copy in the toolchain/ tree.
 #
@@ skipping 479 matching lines @@
       Run(env.get('CC') + env.get('CC_FLAGS'))
     return 0
 
   unmatched = env.get('UNMATCHED')
   if len(unmatched) > 0:
     UnrecognizedOption(*unmatched)
 
   # If -arch was given, we are compiling directly to native code
   compiling_to_native = GetArch() is not None
 
-  if env.getbool('ALLOW_NATIVE') and not compiling_to_native:
-    Log.Fatal("--pnacl-allow-native without -arch is not meaningful.")
+  if env.getbool('ALLOW_NATIVE'):
+    if not compiling_to_native:
+      Log.Fatal("--pnacl-allow-native without -arch is not meaningful.")
+    # For native/mixed links, also bring in the native libgcc to avoid link
+    # failure if pre-translated native code needs functions from it.
+    env.append('LD_FLAGS', env.eval('-L${LIBS_NATIVE_ARCH}'))
+    env.append('STDLIBS', '-lgcc')
+
 
   if not env.get('STDLIB'):
     # Default C++ Standard Library.
     SetStdLib('libc++')
 
   inputs = env.get('INPUTS')
   output = env.getone('OUTPUT')
 
   if len(inputs) == 0:
     if env.getbool('VERBOSE'):
@@ skipping 272 matching lines @@
   -g                    Generate complete debug information.
   -gline-tables-only    Generate debug line-information only
                         (allowing for stack traces).
   -flimit-debug-info    Generate limited debug information.
   -save-temps           Keep intermediate compilation results.
   -v                    Verbose output / show commands.
   -h | --help           Show this help.
   --help-full           Show underlying clang driver's help message
                         (warning: not all options supported).
 """ % (tool)