set path=( /bin /usr/bin /sbin /usr/sbin )

env                                                             \
        CC=$L/bin/gcc-8                                         \
        CONFIGUREFLAGS="--without-isl"                          \
        CXX=$L/bin/g++-8                                        \
        GMPPREFIX=$L/gmp                                        \
        GNAT=$L/bin/gnat-8                                      \
        GNATBIND=$L/bin/gnatbind-8                              \
        GNATMAKE=$L/bin/gnatmake-8                              \
        LANGS=brig,c,c++,fortran,go,lto,objc,obj-c++            \
        prefix=$L                                               \
        $G/gcc/build-dgcc.sh gcc-8-20171112

( chdir $L/bin ; $G/gcc/make-gcc-wrapper.sh gcc-8-20171112 )
( chdir $L/bin/ ; env VER1=8 VER2=8.0 VER3=8.0.0 $G/gcc/make-gcc-links.sh gcc-8-20171112 )

------------------------------------------------------------------------

The build-dgcc.sh script reports:

nice time env CC="$L/bin/gcc-8"                                                 \
              CXX="$L/bin/g++-8"                                                \
              CFLAGS=""                                                         \
              CPPFLAGS=""                                                       \
              CXXFLAGS=""                                                       \
              LDFLAGS="-L$L/lib64 -Wl,-rpath,$L/lib64"                          \
        ../gcc-8-20171112/configure                                             \
                --disable-nls                                                   \
                --enable-decimal-float=dpd                                      \
                --enable-languages=ada,brig,c,c++,fortran,go,objc,obj-c++       \
                --with-gmp=$L/gmp                                               \
                --with-mpfr=$L/gmp                                              \
                --with-mpc=$L/gmp                                               \
                --prefix=$L/ashare/gcc/gcc-8-20171112                           \
                --libdir=$L/ashare/gcc/gcc-8-20171112/lib64                     \
                --without-isl                                                   &&
        nice time $L/bin/gmake -j48 bootstrap