docker image: add m4 package so can build sage
docker image: add m4 package so can build sage

tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc,tscholl2/smc