Add rule for creating SPIRV-Tools generators.inc file
Add rule for creating SPIRV-Tools generators.inc file

This goes with https://github.com/KhronosGroup/SPIRV-Tools/pull/504

dneto0/shaderc,antiagainst/shaderc,dneto0/shaderc,dneto0/shaderc,antiagainst/shaderc,antiagainst/shaderc,dneto0/shaderc,antiagainst/shaderc