Adds a library for spirv-fuzz, consisting of a Fuzzer class that will
transform a module with respect to (a) facts about the module provided
via a FactManager class, and (b) a source of random numbers and
parameters to control the transformation process provided via a
FuzzerContext class. Transformations will be applied via classes that
implement a FuzzerPass interface, and both facts and transformations
will be represented via protobuf messages. Currently there are no
concrete facts, transformations nor fuzzer passes; these will follow.
The 'is' operator is not meant to be used for comparisons. It currently working is an implementation detail of CPython.
CPython 3.8 has added a SyntaxWarning for this.
subprocess.Popen returns byte data by default. Python2 was happy
to try to execute string operations on such data and hope for the
best, but python3 is more persnickety. Luckily, there's a simple
way to indicate to the Popen class that text data is wanted that
benefits the script. Just specifying universal_newlines will cause
the returned data to be text and also convert any system-specific
newlines to '\n' which the script relies on anyway.
Enabled on Mac as an incidental change after confirming that the
script works there just as well as it does on Linux.
It probably works on FreeBSD too, but I retired my BSD system years
ago. So I have no way to check.
Don't run it on Windows.
- It didn't work after all. It was just detecting non-posix and
returning success.
