An empty .gdbinit in the current directory is not effective at
avoiding ~/.gdbinit.  Use the option -nh instead.

an exit status of 1 for compilation of a non-existing file.
This was causing problems with gcc 4.6.3 (and probably other
gcc versions) which was returning exit status 4 in that case.
I changed the test to instead use an existing file and
to expect exit status 0; we don't actually fail the compilation
if a bad log file is specified, instead we just log an error
message about the bad log file on stderr.

since gcc 4.6.3 (and perhaps earlier) returns exit status 4.
Instead, just verify that the exit status from distcc is non-zero
and matches what gcc returned.

* test/testdistcc.py: Remove stale and duplicate TODO items.

  (_Touch): New function, acts like touch(1).
  (Compile_c_Case): makeFile is not sufficient to reliably update
  modification time on all systems (e.g. GNU/Hurd), so replace it with
  calls to _Touch.
  (Gdb_Case): Use _Touch.

  (SyntaxError_Case): Look for pattern anywhere in the output using
  re.search as warnings and other noise can be present.

* test/comfychair.py: Also set LC_ALL, which has a higher priority,
  and make it so LANG and LC_ALL are set after saving the environment.

  Clean up some stray import statements.

Fixes issue 127

handle header file names containing commas.

<http://code.google.com/p/distcc/issues/detail?id=81>:
SyntaxError_Case was failing with recent versions of gcc,
due to the error message format having changed to now
include the column number.

Also remove an old "XXX" comment that no longer applies.