The grammar now accepts type casts, like "(int)x", but that
has to be disambiguated from "(a + b)", needed deeper lookahead
and backing up than what existed so far.

HLSL: Add negative intrinsics tests

HLSL: Fix for empty statement segfault

remapper: do not eliminate interface variables in dce

HLSL: Initial implementation of direct-mapped subset of HLSL intrinsics

this is done by counting op_entrypoint as a use/def

This checkin implements about half of the HLSL intrinsics for a subset of their
entire type support (but a useful subset).  The uncommented lines in
TBuiltInParseablesHlsl::identifyBuiltIns shows which are connected.

Build: For MinGW, statically link exes against basic runtimes

GLSL takes a traditional sampler, but SPIR-V wants just the
sampled image, not the combined sampler and image.

Avoids the need to ship basic runtimes like libgcc_s_sjlj-1.dll
with the executables.

Build: Produce different names for files in debug builds on MSVC

SPV: Fix double matrix creation

This amends the previous commit, which ommitted barriers in version 420 for compute shader.

Core compute shaders were working, but the extension wasn't implemented.

Also beefed up support for running compute shaders is #version 420, but this
work is only partially done.

Make two more IncludeResult members const.

SPV: Don't shadow sampler parameters when performing function calls

Link: Handle multiple ES profile compilation units for a single shader stage

Fixes #179

The test result should only give one error about linking
ES and non-ES shading language compilation units:

 - empty.frag: No version info, interpreted as 100, ES
 - empty2.frag: No version info, interpreted as 100, ES
 - empty3.frag: Version declared as 110, non-ES

Previously, because the new intermediate is always created
without version/profile information, there would be two
linker errors:

 1.) When merging the new intermediate with empty.frag
 2.) When merging (new intermediate + empty.frag + empty2.frag) with empty3.frag

Now, there is only one error; as the error with merging the
new intermediate with empty.frag has been removed.

When linking multiple compilation units per shader stage,
the code creates a new intermediate, but fails to set its
version and profile.

This change makes it so that the new intermediate inherits
the version and profile of the first compilation unit, so
that two ES SL compilation units can be combined.

Vulkan: Finish semantics for what creates spec-const-semantics.

Note: This required adding a new test mode to see the AST for vulkan tests.
This also required reworking some deeper parts of type creation, regarding
when storage qualification and constness is deduced bottom-up or dictated
top-down.

HLSL: Add base class TParseables for intrinsic / builtin generation.

Add stubbed HLSL derivation.  GLSL derivation is still called TBuiltIns,
for historical compatibility.

SPV: Fix an issue of interpolation decoration.

GLSL interpolation qualifiers and auxiliary storage qualifiers are not
mutually exclusive. So when they are translated to SPIR-V decorations, two
independent utility methods should be employed to do this job.

Fixes issue #252.

Build: atoi comes from stddef.h or cstddef