https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68347
--- Comment #9 from Alexey Rychkov <alexey.a.rychkov at gmail dot com> --- (In reply to Dominique d'Humieres from comment #8) > > ... results in valid output. > > So Mikael probably got the point: don't buil in the source directory. > Instead of > > > cd gcc-5.2.0 > > mkdir build && cd build > > ../configure --disable-multilib > > make > > do > > cd gcc-5.2.0 > mkdir ../build && cd ../build > ../gcc-5.2.0/configure --disable-multilib > make > > (or similar!-). Are you sure that problem is not in GREP_OPTIONS='--color=always' which according to man results in color output using default color scheme '01;31'?