Fix -Wignored-qualifier and -Wunused-variable warnings

Appveyor CI: build artifacts for x64

Fixes https://github.com/KhronosGroup/glslang/issues/1396

Non-Functional: Add postprocess as more robust way to add capabilities

When capabilities are needed for specific SPIR-V instructions, it is
fragile to do so based on GLSL/AST usage; it should be based on actual
instructions they got translated to.

Fix various build warnings/errors

1) On some old versions of MSVC:

	glslang\MachineIndependent\Constant.cpp(187): warning C4056: overflow in floating-point constant arithmetic

On this platform the definition of INFINITY is as follows:

	#ifndef _HUGE_ENUF
	   #define _HUGE_ENUF  1e+300  // _HUGE_ENUF*_HUGE_ENUF must overflow
	#endif
	#define INFINITY   ((float)(_HUGE_ENUF * _HUGE_ENUF))

Moving the negation outside the cast seems to resolve that issue.

2) Some Linux compilers were unhappy with lines 226/227

	glslang/MachineIndependent/Constant.cpp: In member function 'virtual glslang::TIntermTyped* glslang::TIntermConstantUnion::fold(glslang::TOperator, const glslang::TIntermTyped*) const':
	glslang/MachineIndependent/Constant.cpp:226:99: error: integer overflow in expression [-Werror=overflow]
			 else if (rightUnionArray[i].getIConst() == -1 && leftUnionArray[i].getIConst() == -(int)0x80000000)
													   ^~~~~~~~~~~~~~~~
	glslang/MachineIndependent/Constant.cpp:227:48: error: integer overflow in expression [-Werror=overflow]
			     newConstArray[i].setIConst(-(int)0x80000000);
	                                                ^~~~~~~~~~~~~~~~

Moving the negation to the right side of the cast made those happy, but then some Windows compilers were unhappy:

	glslang\MachineIndependent\Constant.cpp(226): warning C4146: unary minus operator applied to unsigned type, result still unsigned
	glslang\MachineIndependent\Constant.cpp(227): warning C4146: unary minus operator applied to unsigned type, result still unsigned

which required adding on the "ll" suffix.

3) Android builds where unhappy with line 242:

	glslang/MachineIndependent/Constant.cpp:242:100: error: comparison of integers of different signs: 'long long' and 'unsigned long long' [-Werror,-Wsign-compare]
        	        else if (rightUnionArray[i].getI64Const() == -1 && leftUnionArray[i].getI64Const() == -0x8000000000000000ll)
                	                                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~~~~~
	1 error generated.

Adding an explicit (long long) cast resolved this.
And the negation needs to be on the right side of the cast otherwise linux
builds are unhappy as in (2).

4) Android builds are unhappy with out of order initializers:

	glslang/MachineIndependent/reflection.h:60:84: error: field 'type' will be initialized after field 'stages' [-Werror,-Wreorder]
		glDefineType(pGLDefineType), size(pSize), index(pIndex), counterIndex(-1), type(pType.clone()), stages(EShLanguageMask(0)) { }
											   ^
	1 error generated.


Change-Id: Ic9a05fa7912498284885113d8b051f93f822f62b

Tests: Add more string -> float tests. Related to #1456.

Possibly addresses #1456

Fixes a crash when in/out varying variable had no semantic name and a…

 Match https://github.com/KhronosGroup/GLSL/pull/22

Fixes a crash when in/out varying variable had no semantic name and an error was reported in ioremapper phase when the variable was rejected

GLSL/SPV: If a texture is used with a shadow sampler, force 'shadow'.

Update spirv-tools known good

Tracks https://github.com/KhronosGroup/GLSL/pull/22.

Fixes #854. But, only good if we are not trying to use the same
texture for both shadow and non-shadow constructors.

Force the type of the texture to have 'shadow' set when it is
constructed with a samplerShadow.

Includes the following:

Add Vulkan 1.1 capability sets
Don't merge types of resources
Remove stores of undef.
Make sure the constant folder get the correct type.

Link: Merge all downstream consumed intermediate modes.

Fixes #1309.

build: Add ccache option to CMake config

Link/SPV: Correct symbol IDs on merging ASTs to a single coherent space

CMake options for postfix and SPVRemapper.

Merge branch 'missing_descriptor_indexing_extension' of https://github.com/jeffbolznv/glslang into jeffbolznv-missing_descriptor_indexing_extension

This is one step in providing full linker functionality for creating
correct SPIR-V from multiple compilation units for the same stage.
(This was the only remaining "hard" part. The rest should be simple.)

NDK build: Use NDK r17b and its own CMake toolchain file

More recent NDK releases have their own CMake toolchain file.
Use it.

Also, download the NDK from github.com:dneto0/android-ndk.
That is a fork of the repo we used to use, but we have more
control over how long it stays stable.