nix: added custom build to allow turning off the sandbox

Makefile

@@ -1,29 +1,32 b''
 
-.PHONY: clean test test-clean test-only generate-pkgs pip-packages
+.PHONY: clean test test-clean test-only generate-pkgs pip-packages build-nix
 
 # set by: PATH_TO_OUTDATED_PACKAGES=/some/path/outdated_packages.py
 OUTDATED_PACKAGES = ${PATH_TO_OUTDATED_PACKAGES}
 
 clean:
 	make test-clean
 	find . -type f \( -iname '*.c' -o -iname '*.pyc' -o -iname '*.so' -o -iname '*.orig' \) -exec rm '{}' ';'
 
 test:
 	make test-clean
 	make test-only
 
 test-clean:
 	rm -rf coverage.xml htmlcov junit.xml pylint.log result
 	find . -type d -name "__pycache__" -prune -exec rm -rf '{}' ';'
 	find . -type f \( -iname '.coverage.*' \) -exec rm '{}' ';'
 
 test-only:
 	PYTHONHASHSEED=random \
 	py.test -x -vv -r xw -p no:sugar \
 	--cov=vcsserver --cov-report=term-missing --cov-report=html vcsserver
 
 generate-pkgs:
 	nix-shell pkgs/shell-generate.nix --command "pip2nix generate --licenses --no-binary :all:"
 
 pip-packages:
 	python ${OUTDATED_PACKAGES}
+
+build-nix:
+	nix-build --show-trace --option sandbox false --option max-jobs 4 --option cores 4