https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81421
--- Comment #8 from Ian Lance Taylor <ian at airs dot com> --- On my system I see this: > sed '/^package /q' < ~/gcc/gcc-7-branch/libgo/go/runtime/mksizeclasses.go | > grep '^// +build ' | cat // +build ignore That is, the command displays `// +build ignore`. The fact that it displays nothing on your system is the root of the problem here. You seem to be running GNU/Linux. What versions of sed and grep are on your PATH? The sed and grep commands look simple enough to me. I can't think of any reason why they would fail. What does the sed command print if you run it alone?
