save-build-env: Strip out MAKEOPTS and NINJAOPTS

MAKEOPTS and NINJAOPTS contains a host specific value. If the same
package is built on a host with different core counts, the binpkgs will
have different hashes. This change drops MAKEOPTS after src_install so
that it's not included in final environment.gz. This change also adds
them to the special_env_vars.py so that we always have the most up to
date version of these variables.

Bug: https://bugs.gentoo.org/914441
Bug: https://bugs.gentoo.org/736794
Signed-off-by: Raul E Rangel <[email protected]>

Author: Raul E Rangel

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

@@ -24,6 +24,12 @@ __save_ebuild_env() {
 				unset PYTHONPATH
 			fi
 		fi
+
+		# These variables contains build host specific configuration. We
+		# want binpkgs generated on different sized hosts to be
+		# identical, so strip them from the binpkg. It's also not needed
+		# for installing / removing a package.
+		unset MAKEOPTS NINJAOPTS
 	fi
 
 	# misc variables inherited from the calling environment

Diff for: lib/portage/package/ebuild/_config/special_env_vars.py

@@ -112,7 +112,9 @@
         "FEATURES",
         "FILESDIR",
         "HOME",
+        "MAKEOPTS",
         "MERGE_TYPE",
+        "NINJAOPTS",
         "NOCOLOR",
         "NO_COLOR",
         "P",