Disable task table by default

This commit disables task tracking and the task table by default.
This cuts down on the size of the generated code and compile time
significantly.  The argument is that if your program fails
deterministically enough to be able to re-run with task tracking,
you can afford the time to recompile it.

We could make this default to on for CHPL_TASKS=fifo (the only place
it works currently anyway), but that suggests that once qthreads
supported it, we'd want it to default on there too, and I'm not sure
that's the case.  Or else we'd want to disable it in testing by
default.
Merge branch 'master' of https://github.com/chapel-lang/chapel into noTaskTable
Added a routine to warn if this flag is used when CHPL_TASKS != fifo

(since none of the tasking runtime layers call into this module
other than that one).
Merge branch 'master' of https://github.com/chapel-lang/chapel into noTaskTable
Fix qio_file_path_for_fd so it works in cygwin

qio_file_path_for_fd has three paths that are selected via ifdefs, cygwin was
hitting the fall-back case that always returned "unknown" as the file path.

cygwin can actually use the same code as linux for this operation, so I've
added a check for __CYGWIN__ to that `#if`.
Add a future for the widecols.chpl cygwin output.

Cygwin thinks that the character G clef takes up more
space than it does when output, so is missing a space
in its final output.  This is a bug, so futurize the
failing case (by making a link to the original) and
skip the cygwin run of the original.
Do not insert a nil check before the call to a destructor method
Adjusted the test types/range/bradc/overflowInComputeBlock.chpl.
Attempted fix for portability of uminusVsTimesPrec test

This test has been failing on prgenv-cray due to its reliance on
signed integer wraparound.  The intent of the test is interesting to
me (trying to rationalize relative precedence between unary minus and
multiplication), and a quick promotion of it from an int(32) test to
an int(64) test seems to work for prgenv-cray, so I'd like to try
running it that way to see if it makes it work everywhere.  If it
doesn't, we can decide to either skipif the test or retire it.
Merge pull request #780 from vasslitvinov/update-overflowInComputeBlock.chpl

Adjusted the test types/range/bradc/overflowInComputeBlock.chpl

The test was created to test the fix in r18647 aka SHA1 2287215.
Back then the default integers were 32-bit, and I wasn't sure
that today this test is useful.

I changed the test to use 16-bit integers explicitly,
and verified that it fails if I revert that fix.
So, in this sense, this test IS useful today.

Also I am removing the .skipif that was added recently
to avoid valgrind timeout for this test - it should not
be an issue given this smaller problem size.
Merge pull request #781 from bradcray/attempted-fix-for-uminusVsTimesPrec

Attempted fix for portability of uminusVsTimesPrec test

This test has been failing on prgenv-cray due to its reliance on
signed integer wraparound.  The intent of the test is interesting to
me (trying to rationalize relative precedence between unary minus and
multiplication), and a quick promotion of it from an int(32) test to
an int(64) test seems to work for prgenv-cray, so I'd like to try
running it that way to see if it makes it work everywhere.  If it
doesn't, we can decide to either skipif the test or retire it.
More minor changes based on late returns today
Merge pull request #775 from Kyle-B/kb-cygwin-filepath

Fix qio_file_path_for_fd so it works in cygwin

`qio_file_path_for_fd` has three paths that are selected via `#ifdef`s, cygwin was
hitting the fall-back case that always returned "unknown" as the file path.

cygwin can actually use the same code as linux for this operation, so I've
added a check for `__CYGWIN__` to that `#if`.
Fix prgenv-cray portability issue for glob() call

The glob() call takes an optional function pointer as an argument, and
I had just been passing c_nil into it.  However, the Cray compiler
doesn't like this because of the fact that it isn't a literal "NULL"
being passed in, but a Chapel variable of type void* which isn't
of pointer-to-function type.

As an easy workaround for this, I invented an external type to
represent the function pointer type and declared a (local to the
scope in question) extern var named NULL of that type.  This has
the effect of passing the NULL straight through to glob() which
makes the complaint go away.

If this didn't work on some other platform (though I believe it
will), we could always push the glob() into the runtime, wrapping
it as chpl_glob() and have it supply the NULL argument for the
function pointer.  But the current approach feels more lightweight
without seeming crufty to me.
memleaks testing came back in
Add --task-tracking flag to tests that use it
Update to comments to reflect that these are stubs
Merge pull request #782 from bradcray/glob-for-cray

Fix prgenv-cray portability issue for glob() call

[reviewed by noakes]

The glob() call takes an optional function pointer as an argument, and
I had just been passing c_nil into it.  However, the Cray compiler
doesn't like this because of the fact that it isn't a literal "NULL"
being passed in, but a Chapel variable of type void* which isn't
of pointer-to-function type.

As an easy workaround for this, I invented an external type to
represent the function pointer type and declared a (local to the
scope in question) extern var named NULL of that type.  This has
the effect of passing the NULL straight through to glob() which
makes the complaint go away.

If this didn't work on some other platform (though I believe it
will), we could always push the glob() into the runtime, wrapping
it as chpl_glob() and have it supply the NULL argument for the
function pointer.  But the current approach feels more lightweight
without seeming crufty to me.
Add new flag to expected help message
Merge branch 'master' of https://github.com/chapel-lang/chapel into noTaskTable