MinGW fixes

See merge request !52

On windows the temp file cannot be opened a second time while
it is still opened by python. Close the file in python before
asking the compiler to read it.

See https://docs.python.org/3.7/library/tempfile.html#tempfile.NamedTemporaryFile

Fix wrapper for clCreateProgramWithBuiltinKernels

See merge request !51

Introduce PYOPENCL_STACK_CONTAINER to dispatch VLA/std::vector for opposite compiler needs

See merge request inducer/pyopencl!50

Use std::vector for arrays with non-constant length

See merge request inducer/pyopencl!49

Fixes MSVC build issue

Fix cxxflags handling in pybind11 BuildExt

See merge request inducer/pyopencl!48

Support vector arguments with offset in scan kernels.

See merge request inducer/pyopencl!47

This reverts commit ea24cc51.

This reverts commit 749e6a3e.

Fix bank conflict avoidance

See merge request inducer/pyopencl!46

Fix, test cl{Compile,Link}Program wrappers

See merge request inducer/pyopencl!45

Pybind11

See merge request !44