save-build-env: Strip out non-reproducible variables

Bash provides access to the time and a random data via variables. We
don't want to persist these values when generating a binpkg.

Bug: https://bugs.gentoo.org/914441
Signed-off-by: Raul E Rangel <[email protected]>

Author: Raul E Rangel

Diff for: bin/save-ebuild-env.sh

@@ -30,6 +30,10 @@ __save_ebuild_env() {
 		# identical, so strip them from the binpkg. It's also not needed
 		# for installing / removing a package.
 		unset MAKEOPTS NINJAOPTS
+
+		# These variables are constantly changing. Strip them so we
+		# don't introduce non-reproducible data into the binpkg.
+		unset EPOCHREALTIME EPOCHSECONDS SRANDOM
 	fi
 
 	# misc variables inherited from the calling environment