make.bash: avoid ksh bug in nogoenv

ksh handles make.bash surprisingly well and is a smaller
supply chain attack surface, so it's reasonable to want
to use "ksh make.bash" to build Go.

The only place where ksh and bash disagree in running
make.bash is an arguable bug in ksh that

	X=Y foo

accidentally changes the real value of X following that
command when foo is a shell function. (It correctly preserves
the original value of X when foo is a command being invoked.)

More specifically,

	GOROOT=$GOROOT_BOOTSTRAP nogoenv foo

incorrectly changes $GOROOT in the rest of the script.

CL 580020 suggested using a subshell, but subshells
historically have lost "set -e", so we'd have to use (...) || exit 1.
Instead of that, this CL refactors nogoenv into bootstrapenv,
putting it in charge of changing $GOROOT the same way it
changes all the other environment variables.

This CL also updates make.rc for parallelism.
It does not bother updating make.bat: that part is already
a bit different, and attempting to change it is all risk, no reward.

Change-Id: I5923a6fb5016a3862363363859365d1cd4f61a1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/582076
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Eric Grosse <grosse@gmail.com>

0 files changed, 0 insertions, 0 deletions