Use libspirv::CapabilitySet instead of a 64-bit mask.
Remove dead function spvOpcodeRequiresCapability and its tests.
The JSON grammar parser is simplified since it just writes the
list of capabilities as a braced list, and takes advantage of
the CapabilitySet intializer-list constructor.
For fulfilling this purpose, the |opcode| field in the
|spv_parsed_instruction_t| struct is changed to of type uint16_t.
Also add functions to query the information of a given SPIR-V
target environment.
Now we have public headers arranged as follows:
$SPIRV_TOOLS_ROOT/include/spirv-tools/libspirv.h
$SPIRV_TOOLS_ROOT/include/spirv/spirv.h
$SPIRV_TOOLS_ROOT/include/spirv/GLSL.std.450.h
$SPIRV_TOOLS_ROOT/include/spirv/OpenCL.std.h
A project should use -I$SPIRV_TOOLS_ROOT/include
and then #include "spirv-tools/libspirv.h"
The headers from the SPIR-V Registry can be accessed as "spirv/spirv."
for example.
The install target should also install the headers from the SPIR-V
Registry. The libspirv.h header is broken otherwise.
The SPIRV-Tools library depends on the headers from the SPIR-V Registry.
The util/bitutils.h and util/hex_float.h are pulled into the internal
source tree. Those are not part of the public API to SPIRV-Tools.
