Make spec file optional
Make spec file optional

shurikasa/CMake,shurikasa/CMake,tribal-tec/vmmlib,jafyvilla/CMake,rballester/vmmlib,BlueBrain/Tuvok,biddisco/CMake,shuaibarshad/KAUST-CMake,ptoharia/CMake,hernando/vmmlib,shurikasa/CMake,BlueBrain/Tuvok,BlueBrain/Tuvok,ptoharia/CMake,shuaibarshad/KAUST-CMake,hernando/vmmlib,shuaibarshad/KAUST-CMake,shurikasa/CMake,biddisco/CMake,rballester/vmmlib,hernando/vmmlib,biddisco/CMake,jafyvilla/CMake,jafyvilla/CMake,rballester/vmmlib,shuaibarshad/KAUST-CMake,biddisco/CMake,ptoharia/CMake,jafyvilla/CMake,ptoharia/CMake