Fix a few regressions from enabling macro modularization#53270

Merged

bors merged 3 commits intorust-lang:masterfrom

petrochenkov:macuse-regr

Aug 13, 2018

Commits on Aug 11, 2018

Feature gate arbitrary tokens in non-macro attributes with a separate gate
petrochenkov
committed
Do not consider built-in attributes as candidates when resolving non-attribute macro invocations
petrochenkov
committed

Commits on Aug 12, 2018

Prohibit using macro-expanded `macro_export` macros through module-relative paths
petrochenkov
committed