merge from gcc

libdecnumber/ChangeLog

libdecnumber/decBasic.c

libdecnumber/decCommon.c

libdecnumber/decContext.c

libdecnumber/decContext.h

libdecnumber/decDPD.h

libdecnumber/decDouble.c

libdecnumber/decDouble.h

libdecnumber/decNumber.c

libdecnumber/decNumber.h

libdecnumber/decNumberLocal.h

libdecnumber/decPacked.c

libdecnumber/decPacked.h

libdecnumber/decQuad.c

libdecnumber/decQuad.h

libdecnumber/decSingle.c

libdecnumber/decSingle.h

libdecnumber/dpd/decimal128.c

libdecnumber/dpd/decimal128.h

libdecnumber/dpd/decimal32.c