Add regression test for issue #4154.

cabal-testsuite/PackageTests/Regression/T4154/cabal.project

+packages: .

cabal-testsuite/PackageTests/Regression/T4154/install-time-with-constraint.test.hs

+import Test.Cabal.Prelude
+
+-- Test that unqualified command line constraints do not constrain setup
+-- dependencies. cabal should be able to install the local time-99999 by
+-- building its setup script with the installed time, even though the installed
+-- time doesn't fit the constraint.
+main = cabalTest $ withRepo "repo" $
+       cabal "new-build" ["time", "--constraint=time==99999", "--dry-run"]

cabal-testsuite/PackageTests/Regression/T4154/repo/Cabal-99999/Cabal.cabal

+name:            Cabal
+version:         99999
+cabal-version:   >=1.8
+build-type:      Simple
+
+library
+  build-depends: base, time

cabal-testsuite/PackageTests/Regression/T4154/time.cabal

+name:            time
+version:         99999
+cabal-version:   >=1.8
+build-type:      Custom
+
+custom-setup
+  setup-depends: base, Cabal == 99999
+
+library
+  build-depends: base