Avoid depending on another NaCl toolchain for gdb

Disable GDB tests by default and when they are disabled don't try to
look for a 2nd NaCl toolchain just to grab its GDB.

GDB tests on Linux are broken for me anyway in upstream with the
incompatibly old curses lib dependency issue.

Author: slipher

SConstruct

@@ -382,7 +382,7 @@ def SetUpArgumentBits(env):
       'to run the specified test(s) without actually running them.  This '
       'argument is a counterpart to built_elsewhere.')
 
-  BitFromArgument(env, 'no_gdb_tests', default=False,
+  BitFromArgument(env, 'no_gdb_tests', default=True,
     desc='Prevents GDB tests from running.  If GDB is not available, you can '
       'test everything else by specifying this flag.')
 

site_scons/site_tools/naclsdk.py

@@ -755,7 +755,8 @@ def FakeInstall(dest, source, env):
   else:
     _SetEnvForNativeSdk(env, root)
 
-  if (env.Bit('bitcode') or env.Bit('nacl_clang')) and env.Bit('build_x86'):
+  # Daemon: don't depend on a second NaCl toolchain!
+  if (env.Bit('bitcode') or env.Bit('nacl_clang')) and env.Bit('build_x86') and not env.Bit('no_gdb_tests'):
     # Get GDB from the nacl-gcc glibc toolchain even when using PNaCl.
     # TODO(mseaborn): We really want the nacl-gdb binary to be in a
     # separate tarball from the nacl-gcc toolchain, then this step