cmake HAVE_SIGEV_PORT examples

google/mysql-protobuf configure.cmake :504 

CHECK_SYMBOL_EXISTS(SIGEV_PORT "signal.h;time.h;sys/siginfo.h" HAVE_SIGEV_PORT)

mongodb/mongo-bi-connector-odbc-driver configure.cmake :536 

CHECK_SYMBOL_EXISTS(SIGEV_PORT "signal.h;time.h;sys/siginfo.h" HAVE_SIGEV_PORT)