src/buildall.bash: use grep -E instead of egrep
according to https://www.phoronix.com/news/GNU-Grep-3.8-Stop-egrep-fgrep egrep and fgrep should not be used anymore. thats why using buildall.bash throws the following warning: egrep: warning: egrep is obsolescent; using grep -E
Change-Id: I2f3be55ebaa7826a7f89a93d756e083b9bddfb03
GitHub-Last-Rev:
60be0651afd68671dce2e701f9b8bfe1c16a3da8
GitHub-Pull-Request: golang/go#66990
Reviewed-on: https://go-review.googlesource.com/c/go/+/581055
Reviewed-by: Joedian Reid <joedian@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>