Only use gcc to compile mutatees on linux (#148)

Clang _should_ work, but it will be added later. The test suite will not compile with any other compiler.

CMakeLists.txt

@@ -331,22 +331,6 @@ if(UNIX)
   message(STATUS "Mutatee gcc: ${M_gnu_cc}")
   find_program(M_gnu_cxx NAMES g++)
   message(STATUS "Mutatee g++: ${M_gnu_cxx}")
-  find_program(M_intel_cc NAMES icc)
-  message(STATUS "Mutatee icc: ${M_intel_cc}")
-  find_program(M_intel_CC NAMES icpc)
-  message(STATUS "Mutatee icpc: ${M_intel_CC}")
-  find_program(M_pg_cc NAMES pgcc)
-  message(STATUS "Mutatee pgcc: ${M_pg_cc}")
-  find_program(M_pg_cxx NAMES pgCC)
-  message(STATUS "Mutatee pgCC: ${M_pg_cxx}")
-  find_program(M_mpi_cc NAMES mpicc)
-  message(STATUS "Mutatee mpicc: ${M_mpi_cc}")
-  find_program(M_mpi_cxx NAMES mpicxx)
-  message(STATUS "Mutatee mpicxx: ${M_mpi_cxx}")
-  find_program(M_mpi_xlc NAMES mpixlc)
-  message(STATUS "Mutatee mpixlc: ${M_mpi_xlc}")
-  find_program(M_mpi_xlcxx NAMES mpixlcxx)
-  message(STATUS "Mutatee mpixlcxx: ${M_mpi_xlcxx}")
 elseif(WIN32)
   find_program(M_native_cc NAMES cl)
   find_program(M_native_cxx NAMES cl)