CL 432835 changed two grep commands in unix/mkerrors.sh in such a way
that is incompatible with AIX's grep, which, unlike GNU grep, does not
support extended regular expressions without the -E flag. The intent of
this PR is to restore the egrep behavior by invoking grep as grep -E.
My assumption is that GNU grep is not meant to be a requirement to run
mkerrors.sh, and given that, grep -E looks like the most cross-platform
approach.
Example of current (incorrect) behavior on AIX:
bash-5.2$ printf 'SIGHUP\nSIGMAX64\nSIGTERM' | grep -v 'SIGSTKSIZE\|SIGSTKSZ\|SIGRT\|SIGMAX64'
SIGHUP
SIGMAX64
SIGTERM
Behavior before CL 432835:
bash-5.2$ printf 'SIGHUP\nSIGMAX64\nSIGTERM' | egrep -v '(SIGSTKSIZE|SIGSTKSZ|SIGRT|SIGMAX64)'
SIGHUP
SIGTERM
Behavior of proposed change:
bash-5.2$ printf 'SIGHUP\nSIGMAX64\nSIGTERM' | grep -E -v '(SIGSTKSIZE|SIGSTKSZ|SIGRT|SIGMAX64)'
SIGHUP
SIGTERM
OpenBSD's grep behaves the same as AIX for the above commands, which is
why I cast this as GNU vs. non-GNU. I haven't tested any other
implementations.
Fixesgolang/go#69365
Change-Id: I009353ee630463475a5c131d019f59c5e69efd34
GitHub-Last-Rev: e1166046e1f6d97d0efe28f96e692f2df790be6f
GitHub-Pull-Request: golang/sys#217
Reviewed-on: https://go-review.googlesource.com/c/sys/+/615755
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
