cmake HAS_SPEC_EXPORTER examples

sxs-collaboration/spectre src/Evolution/Executables/GeneralizedHarmonic/CMakeLists.txt :98 

target_compile_definitions(
    ${BBH_EXECUTABLE} PRIVATE HAS_SPEC_EXPORTER)

sxs-collaboration/spectre src/IO/External/CMakeLists.txt :28 

target_compile_definitions(
    ${LIBRARY} INTERFACE HAS_SPEC_EXPORTER)